b2evolution's development efforts have been moved to sourceforge.net lately. So if you're interested in contributing, localizing or even just in the latest cutting edge releases, feel free to visit: https://sourceforge.net/projects/evocms/ .
Actually the hot spot is the CVS repository. If you're unfamiliar to CVS and sourceforge.net you'll be able to find introductory information on this page: https://sourceforge.net/cvs/?group_id=85535 .
CVS will let you seemlessly update your b2evolution test/develoment platform with the daily new enhancements.
Right now, for example, the CVS version has full internationalization/localization support... and a few translations are already available. 
Please note however that you should only use the CVS version of b2evo for testing and development purposes. You should always wait for stable (normal) releases before putting it into production.
...that is unless you know what you're doing of course 