I'll start releasing what I have so far in a couple of days. All the code will be available under the GPL.
I'm going to be writing two backends: Perl (LiveJournal specific, likely) tand HTML (for pretty-printing). Once I get those mostly functional, I'd like to get some ASP, PHP, and Servlet backends started. The interface between the backends is perfectly clean (I love Java. :-)) so it should be pretty easy.
I'll be javadoc'ing my code, and maintaining an EBNF of the S2 grammar, both of which I'll make available in a few days.
Damn it feels good to stop doing sysadmin stuff. :-) I seriously need to find somebody to take over that job for me.... I don't enjoy it at all.