It’s being said a lot these days: The next billion cell phone users won’t come from the developed world, because so many of us have phones already. That next wave will come primarily from China and India.

With that in mind, today I talked to Bill Krenik, wireless and advanced architectures manager at Texas Instruments (TXN), about the just-announced second version of its single-chip cell phone platform, called eCosto.

The first version, the affordable and tiny LoCosto (photo above) is now shipping, and is for un-subsidized phones that cost as little as $30. (Think phones without cameras, many without color screens.) You won’t see many phones based on this chip in the U.S.; here, our cheapest phones are often worth $150 or so, and carriers give them to subscribers for free when they sign up for multi-year service plans. TI disclosed for the first time that 15 phone manufacturers have embraced the LoCosto chip with 30 phone designs in development; Nokia and at least a couple more top-five phone manufacturers are on that list of 15, though TI wouldn’t give more details.

• eCosto: Phones in 2008

This time around, eCosto – about the same size and sure to be similarly cheap – targets phones for users (many in the developing world) who will want to do a little more with a phone. It supports a color screen, 2D games and a camera, and phones built on it could even include Bluetooth wireless and GPRS service for higher-speed connectivity and data services. Phones with more video and music capabilities should be possible with eCosto.

It sounds like today’s entry-level phones, at a third of the price to build. Krenik said eCosto should be sampling in the first half 2007, with production before end of 2008.

The beauty of these single-chip options is that they’re cheap enough that they make technology available to far more of the world’s population.

According to In-Stat, China is the world’s largest cell phone market with 400 million subscribers, a number that should jump to 600 million by 2008. That growth is coming at both the high and low ends of China’s handset market. China is the fastest growing market for low-priced cell phones, while its younger urban consumers are also starting to snap up higher-end phones with cameras and MP3 players.