SDK revision 3, which is required for building applications for Android 2.0, supports coding using the Ant build system or Mac OS X 10.6. Additionally, Google is releasing its Android Development Tools as a plug-in for the Eclipse development environment.

2.0 Update By Year-End

Android 2.0 is starting to appear on new devices, such as the upcoming Droid from Verizon Wireless that has been making headlines for its "iDon't" commercials comparing its capabilities to those of Apple's iPhone. On its Android Developers Blog, Google said that upcoming Android devices will run versions 1.5, 1.6 or 2.0, and that it expects to offer a minor 2.0 update before year's end.

Android 2.0 offers a variety of enhancements as Google moves to better position the platform in the increasingly competitive struggle for features and applications among mobile devices. The newest Android allows multiple accounts to be added to a device for e-mail and contact syncing, including Microsoft Exchange accounts if the device manufacturer has added that support , and there is support for a combined inbox of those multiple accounts.

Also offered are new developer APIs for applications that allow users to sync their mobile devices with contacts and other data on other machines. Quick Contact provides instant access to the contact information of someone whose photo is tapped for calling, messaging or e-mailing. And a new Bluetooth API adds peer-to-peer connectivity or gaming.

Camera functions supported in Android 2.0 include built-in flash, digital zoom, white balance, and macro focus.

'Most Credible Challenge To the iPhone'

The new Android virtual keyboard has what Google called "an improved keyboard layout," including multi-touch support that allows double key presses to count when typing quickly with two fingers. The built-in dictionary has gotten smarter, with the ability to learn from word usage and auto-suggestion of contact names.

The new user interface includes an "actionable browser URL bar" so users can tap the address bar for instant search. There are also bookmarks with thumbnails of Web pages, and support for double-tap zoom and HTML 5.

Jeffrey Hammond, an analyst with industry research firm Forrester, said "it's going to be cool" to see the newest version of Android in new phones such as the Droid.

"At this point," he said, Android 2.0 "represents the most credible challenge to the iPhone platform." There are some advantages for Android compared to the iPhone, he said, such as Android's "ability to have multiple applications" operating simultaneously.

Hammond noted that another competitive advantage is that, since Android is "modified Java," any developer familiar with Java is going to have "a lot shorter" path developing for that platform than for the iPhone.