Mapdroid lets you view maps from OpenStreetMap on your Android smartphone.
You can download a debug build of Mapdroid. It's not perfect, but hopefully it can help you find your way around, or check for missing features in OpenStreetMap.
2010-11-03:
You might like to be aware of the known bugs.
git clone git://tedp.id.au/git/mapdroid.git
Mapdroid is also available on Github for easy tracking. Check out Mapdroid on Github.
You can contact me by email at ted@tedp.id.au.
Mapdroid is open source, covered by the LGPL.
Have fun!
— Ted Percival.