Pandora, the streaming music radio service, has announced that its Android application is complete. The news comes just over a year since it released its iPhone application. It's available in the Android application market right now.

Unlike streaming music service Spotify, Pandora isn't on-demand. Instead, you pick an artist or song that you like and it builds a radio station around that - with artists and songs that are sonically similar to your selection.

Playback can be controlled by a home-screen widget, you can discover similar artists from the main Android music player, and there's also the option of making your saved stations appear on the home screen via a smart folder, or sharing them with your friends.

The other benefit of Pandora on Android, over the iPhone, is that you can listen in the background. On the iPhone version, if you get a text or an email that you want to reply to then you have to stop the music and switch out, then switch it back on again when you're done.

The Android app is available now on the G1 and myTouch in the US. When the HTC Hero arrives on Sprint, it should work on that, too. The app remains unavailable in the UK, as with the Pandora web service, thanks to prohibitive UK music streaming rates that led to the company pulling out of the country several years ago.