Droid-Fu offers both support classes meant to be used alongside existing Android code, as well as self-contained, ready-to-be-used components like new adapters and widgets.
The areas tackled by Droid-Fu include:
application life-cycle helpers
support classes for handling Intents and diagnostics
better support for background tasks
super-easy and robust HTTP messaging
powerful caching of Objects, HTTP responses, and remote images
custom adapters and views
I suggest you read this introductory article, and anything that follows.