Google released a developer preview of the next version of Android, officially adding the "cupcake" features to the operating system's SDK that have been a vague reality for Android users since late last year.

Yesterday evening, Android developer Xavier Ducrohet announced that developers can now download an early version of the Android 1.5 SDK, based upon the Cupcake branch of the Android Open Source Project.

While not as prolific as Apple's iPhone 3.0 update, Android 1.5 introduces APIs for a large number of top-notch features, such as soft keyboards, home screen widget creation, live folder population, interactive MIDI playback, video recording, and support for speech recognition libraries.

"Cupcake" was a development branch of Android that mirrored what was being worked on by Google privately, which the company promised to merge into the main code at an unspecified date. Cupcake was open sourced in the fourth quarter of 2008, so some developers have already created products available to Android users that offer skeletal versions of the features promised in Android 1.5.

Alternative home screen programs such as aHome have already given users a taste of what this update will offer, by including an on-screen keyboard, velocity-based screen swap, a "side drawer" for applications, and the promise of new "add to home screen" functions like Live Folders and Applications.

Ducrohet encourages developers to dig in, but warns that the APIs are not finalized, so any applications based upon this first look may not even work when the final 1.5 SDK is released at the end of this month.