In addition to translating the website itself, you can also translate language resources such as phrasebooks, vocabulary lists, and stories. Everyone's welcome to do so!
If anybody is having problems with the Translation & Development Center, then you can report so in this thread. The system has been silently operational for over a month, so most bugs should have been eliminated already, but some small issues might pop up still.
In the time the system has been online, various people have already contributed, you can always see who updated what on the news page.
For those who are curious, here is a small screen-shot of the Translation & Development Center in action:
