You can also go to
www.slappyto.net and
www.lignedebasse.com (ligne de basse means bass lines).
I'm on both of them.
lignedebasse.com is an interesting concept. Every month they publish a playback with no bass line and every participant will publish its bass line on top of the playback.
Then everyone will comment trying to help everybody improving his performance.
They are noobies and very experienced bass players, and it is very interesting to see how anybody will work on the same bass line. And it will force you to play different styles that would normally not practice.