Google has published the source code of Android 2.0 - the next version of its operating system, and the one that appears on the recently-released Motorola Droid. Until now, only Motorola and HTC had access to the source, but Google has just opened it up for everyone.

The software update features multiple email accounts, exchange support, new address book functionality, a combined inbox, better search, an improved camera, an improved keyboard, a better browser, and more useful calendar, as well as Bluetooth 2.1, better media playback, and more options for developers.

Hackers have already ported the update over to the G1, the very first Android handset to be released. The team behind the port - Cyanogen - said that the handset runs "really well, fast and smooth" with the 2.0 software. They haven't yet got audio/video playback working, but it's likely not to be far away.

For those unwilling to hack their handsets, though, you'll need to wait for a patch from your phone manufacturer. Expect one to be on the way - we'll let you know when they're released.