Blogger-analyst Andy Zaky, whose earnings estimates for Apple (AAPL) this year have proved considerably more accurate than the professionals' (see here), is predicting "the mother of all earnings blowouts" when the Christmas quarter's results come in.

In a preliminary report published Monday on Seeking Alpha and his blog Bullish Cross, Zaky estimates that when Apple releases its fiscal 2009 Q1 results in January, it will report earnings of $1.96 per share on sales of $11.29 billion — significantly higher than the $1.44 EPS on $10.08 billion that the pros are currently modeling.

"That would be the largest revenue beat by any company I've ever seen," writes Zaky, who attributes the gap between his numbers and the Street's to "irrational bearish exuberance."

Shrugging off concerns about consumer spending this quarter, Zaky is calling for sales growth in all three of Apple main product lines:

• iPods: 22 million units (up from 11.05 million in Q4)
• Macs: 2.8 million (up from 2.61 million)
• iPhones: 8 million (up from 6.89 million)

Note that Zaky, as the name of his blog suggests, is bullish — and long — on Apple and tends to err on the side of optimism. His 2008 Q4 predictions overshot actual results for both iPhones (7.5m est. vs. 6.89m act.) and Macs (2.9m est. vs. 2.61m act.).

[Wall Street, by contrast, is betting that iPhone unit sales -- like geese -- will head south this winter. On Friday, Barclays Capital trimmed its Q1 estimate to 5 million iPhones from 6.2 million. (link)]

But even Zaky's Q1 sales estimate of $11.29 billion pales beside what he calls Apple's "real" sales and earnings. These are the adjusted — or non-GAAP — numbers that Apple released for the first time last quarter. They include deferred revenue from sales of iPhones — which by generally accepted accounting principles (GAAP) are spread out over 24 months (see The day Apple released its iPhone revenue bomb).

When Zaky estimates Apple's earnings using non-GAAP numbers, the gap between the Street's "consensus" and his "reality" grows even wider. As the table below shows, Zaky is calling for non-GAAP sales of $15.22 billion and earnings of an astonishing $3.54 a share.

The only Wall Street analyst I've found who has projected non-GAAP earnings for this quarter is Piper Jaffray's Gene Munster. He has Apple earning $2.70 per share (non-GAAP) in Q1 on adjusted sales of $12.4 billion.

For Zaky's complete analysis — including bullish and bearish scenarios — see his full report at Bullish Cross here.

Here's a chart that should keep Steve Ballmer up at night.

It compares Microsoft's (MSFT) market share, revenue, net profit and growth rate to Apple's (AAPL), using the numbers from each company's most recent quarterly report.

Although Apple has a bit more cash on hand ($24.5 billion v. $20.7 billion), Microsoft's operating system still dominates. And if you use generally accepted accounting principles (GAAP), Redmond's revenue and net income still dwarf Cupertino's.

But it turns out that Apple has been hiding most of its iPhone revenue behind subscription-based accounting (see here). As Apple Insider's Prince McLean points out, if you use the non-GAAP deferred revenue numbers that Apple released last week (and are shown in this chart), the company now earns more than half of Microsoft's profits on more than three fourths of its revenue (see Apple earnings, profits, and cash embarrass Microsoft).

Steve Jobs' company is also growing much more quickly than Ballmer's. Microsoft's revenue grew 9% year over year last quarter. Apple's grew 75%.

Some Apple watchers have complained almost since the launch of the iPhone that Wall Street doesn't understand the device's value to the company. Analysts consistently underestimate Apple's revenue, these investors insist, because they fail to fully account for iPhone sales.

The problem has been festering for so long — and the gap has grown so large between Apple's actual earnings and the Street's grasp of those earnings — that Apple finally let the cat out of the bag Tuesday during its quarterly earnings call.

Measured by so-called generally accepted accounting principles (GAAP), the company earned $1.26 a share in 2008 Q4 on revenue of $7.9 billion. This is the form in which Apple (AAPL) has always reported its income.

But on Tuesday, for the first time, the company went one step further. CFO Peter Oppenheimer told analysts that when measured by actual revenue — counting the full value of every iPhone and Apple TV sold in the quarter — the company earned a good deal more: $2.69 per share on sales of $11.68 billion (see transcript here).

The consensus among analysts before the earnings call was that Apple's revenue for the quarter would be about $8.05 billion. Some traders looked at $7.9 billion and thought Apple had fallen short of the Street's target by $150 million. The smart ones looked at $11.682 billion and realized they'd underestimated Apple's earnings by nearly $3.8 billion. They're probably the reason Apple's share price jumped 12% in after hours trading.

How could the analysts have been so wrong?

In the analysts' defense, the accounting methods Apple uses aren't easy to follow — even though Oppenheimer has spelled them out at almost every earnings call.

For reasons that have to do with being able to provide free upgrades over the life of the phone, Apple doesn't book the full value of, say, a $199 iPhone the day it's sold. Rather, its accountants spread that income out over 24 months, booking $8.29 in the first month, $8.29 the second month, and so on until the revenue from that iPhone has been fully accounted for. (Actually, the value of that iPhone is probably closer to $500, once AT&T has paid its share, but you get the idea.)

Given that Apple's iPhone sales have been growing exponentially over the past 15 months and that each month's iPhone revenue includes not just a share of the sales from that month, but a share of iPhone sales from each of the months that preceded it, you begin to see the dimensions of what one might call Apple's iPhone revenue bomb.

"This is a pretty big deal," Steve Jobs told analysts and journalists on Tuesday, as he made his first appearance at an Apple earnings call in 8 years to try to explain the iPhone's so-called subscription accounting system.

"As long as our iPhone business was small relative to our Mac and music businesses, this didn’t really matter much. But this past quarter, as you heard, our iPhone business has grown to about $4.6 billion, or 39% of Apple's total business, clearly too big for Apple management or investors to ignore."

Oppenheimer and Jobs promised to provide adjusted revenue numbers — so-called non-GAAP revenue — every quarter going forward. But they didn't provide any non-GAAP numbers from quarters past, making it difficult to gauge how fast Apple is actually growing.

That's where Andy Zaky comes in. An amateur Apple watcher — and one of the blogger-analysts who humiliated the professionals in a Q4 earnings estimate smackdown earlier this week (see here) — Zaky stayed up all night Wednesday trying to reconstruct Apple's actual earnings in quarters for which it didn't provide non-GAAP data.

His results, published early Thursday on his blog Bullish Cross, and republished by AppleInsider and Seeking Alpha, show that Apple's revenue actually grew 75% year-to-year last quarter, not the 27% that the company reported, while its real net income grew nearly 125%. The pros could learn a lot by studying his findings.

Zaky's results are summarized in the chart below. To see how he arrived at his numbers, click here.