Currently scheduled for 2008.
I'm of two minds on the subject. There are big chunks of it done already, and big chunks still left to finish; I kind of don't want to release any of it until I have a final-draft candidate so that people don't miss minor changes between drafts.
Although, what I might do is release bits and pieces in the wiki or in the threads here so I can get feedback on some of the more controversial changes. The Charge rules got changed pretty substantially (hopefully they're actually useable now), and I finally hit on some Fire rules that I think are playable (but may be unbalancing because of the simplifications involved). I'm still weighing options.
Another thing I need to do is keep the first post in this thread better updated as the rulebook loadout evolves. Maybe I'll go work on that a little.
edit: nah, never mind. Instead I think I need to go over to the wiki and make a fancy dev update page like the one for dwarf fortress