IDrive Lite, the multi-device contacts backup and restore application for the mobile platforms, now supports Android 2.0 and higher devices, in addition to iPhones and Blackberries.

While there are possibly other contact backup applications, the key differentiating factor is its ability to do cross platform backups and restores. You can backup contacts from your Blackberry and restore it onto your iPhone, a handy feature if you are switching devices, and you can do this wireless.

The Android IDrive Lite application is available via the Android Marketplace  and is  free.  A demo is available here.