Today T-Mobile announced the second "Google phone", the MyTouch 3G. Like the G1, it's built on Google's Android operating system--an open-source platform for mobile devices that's intended to allow for extensive customization and application development.

Clearly timed to compete with the new iPhone release, the MyTouch will sell for $199, and boasts a touch screen, applications available through the Android store, and, of course, 3G access. Existing T-Mobile customers will be able to reserve the phone starting July 8.

It'll be interesting to see how the existence of two Android phones affects the market. Some people may have hung back from purchasing the first Android phone, the T-Mobile G1, due to uncertainties about how the platform would evolve.