The first San Francisco-area Matasano-inspired BaySec get together is Wednesday May 16 2007, 7:00 PM at Zeitgeist. They tell me they don't do reservations, and the best thing is to show up early and stake out your seats. Sounds like an invitation to take over the place to me.
Likely attendees (aka those of us who have been conspiring to get BaySec started) are Raffael Marty, Anton Chuvakin, Nate Lawson, and more importantly, you.
There's a mailing list, courtesy of Tom Ptacek:
baysec at sockpuppet dot org
baysec-subscribe at sockpuppet dot org
Hope to see you there, and please spread the word.