All that remains is writing documentation (or really, merging all the misc docs into something cohesive) and eventually getting developers exciting about it.
The excitement generation can wait a bit, but if you're wanting to get started, here are some initial docs:
http://www.picpix.com/doc/s2.html
You'd need a PicPix.com account to test, unless you're running your own FotoBilder installation.
However, never fear ---
mart has already made the first draft of the core layer for LiveJournal, so we should be having some S2 fun here in LJ land soon.