macromedia.flash (newsgroup) An all-ages show, with some very patient flash masters and much much noise.
flashkit .com A much more advanced group . Not for newbies. A rich web site with excellent discussions and heaps of resources. Also a conference in Sydney and Los Angeles, that addresses the accomplished Flash user .
figtree.com Top educators in advanced ActionScript (like Brendan Hall). The real thing.
moock .com Colin Moock approaches technology with creativity and generosity.
flashforward (conference) Held in both San Francisco and New York and drenched in information and attitude. Wear black, be pierced, and make sure it can all be expensed.