I'm using pygame with a Space Mouse (which, in principle, is the same as
a Spaceball). However, this can't be accessed like a joystick, instead I
was wrapping the SDK by 3dconnexion (the module is available here:
http://cgkit.sourceforge.net/). Unfortunately, this SDK is only
available for Windows. Another drawback is, it only works with a patched
version of pygame as the official version doesn't allow receiving
arbitrary system events. I've sent the patch to the pygame people, but I
believe it wasn't applied yet (I just wanted to check, but the CVS
repository doesn't seem to be available anymore via web...).