Back to the future: Straight Talk phones like the LG 200C might be dowdy, but growth in the prepaid market could eventually squeeze carrier profits. Photo: LG.

Look out, U.S. wireless carriers: Wal-Mart is teaming up with billionaire Carlos Slim’s América Móvil to train its price-crushing might on cell phones.

In time for the holiday season, the mega-retailer on Wednesday announced a nationwide roll-out of the new prepaid Straight Talk service, offered through América Móvil subsidiary Tracfone Wireless. Unlike mainstream wireless plans that pair cutting-edge phones with higher monthly fees and multi-year contracts, pre-paid services like Straight Talk offer cheaper phones, lower fees and no contracts.

Wal-Mart will offer two Straight Talk options: a $30 monthly plan that comes with 1,000 minutes, 1,000 texts and 30 megabytes of data, and a $45 monthly plan with unlimited voice, texts and data. Straight Talk uses Verizon’s (VZ) wireless network. More

Carlos Slim has app envy.

During my interview with AT&T (T) CEO Randall Stephenson at Fortune's Brainstorm TECH conference, he said he was in possession of something that was the envy of his one-time boss, TelMex's (TII) Carlos Slim Helu: an iPhone app.

Okay, it isn't just any old app for Apple's (AAPL) phone. Stephenson's tech folks helped build him a special application that tracks the companies in AT&T's "ecosystem" – partners, competitors, etc. The digital list was inspired, in part, from a paper map that Slim carries around with the names and financial metrics of companies in his universe.

Apparently at a recent meeting, Slim (who is one of the richest men in the world) pulled out his paper, and Stephenson noted that some of the information was out of date. Stephenson pulled out his iPhone and provided some of the updated information from his app. According to Stephenson, Slim (a former technophobe who apparently has become an active BlackBerry user) was definitely desirous of Stephenson's technology.

Possible opportunity for BlackBerry app developers? As Stephenson pointed out on the panel, Slim does have a dollar or two to spare.

There's a Sherman Adams-style political controversy heating up in South America in which the role of the vicuna fur coat is played by a MacBook Air.

The star is Cristina Kirchner, the president of Argentina — the second woman to hold that office (after Isabel Martinez de Peron).

The supporting role is played by Mexican billionaire Carlos Slim, the second richest man in the world, who controls Telefonos de Mexico (TMX) and thus telecommunications over much of Latin America. His name came up in association with Apple earlier this month when Steve Jobs chose his wireless spinoff, America Movil (AMX), to bring the iPhone to 16 countries in Central America, South America and the Caribbean. (see here)

The story begins when billionaire Slim gave President Kirchner the gift of a slim, elegant MacBook Air. The Argentine press got hold of a photograph of the event and began stirring up trouble for La Pinguina, as they have nicknamed her (because of her husband's roots in southern Argentina).

The issue, for several Argentinian newspapers (see here, for example, in Spanish) is whether a MacBook Air, which can fetch more than AR$9,600 in the devalued Argentinian dollar ($3,096 in U.S. dollars), should be considered a "luxury item" — something the President is forbidden by article 256 of the Penal Code to accept as a personal gift.

The code is usually invoked for really big items, like the $120,000 red Ferrari one of her predecessors, Carlos Menem, was forced to turn over to the state.

At least one Argentinian lawyer has come to Kirchner's defense, arguing that by comparison a MacBook Air might be considered just a "courtesy," a thing of "little value." (see here)

Maybe in Argentina.

Anway, thanks for the tip goes to Investor Village's boxerconan, who sees the whole thing as more free publicity for Apple (AAPL). Thanks also to macenstein for the link to the photograph. For more on the story, see huibert-aalbers.com.