You can find links to all the knit- and crochet-alongs based on Interweave's books at: http://www.interweave.com/knitalong/
Some are more active than others (particularly in the first year after a book comes out). Although even some older titles, like Favorite Socks, have fairly active members. The three new knit-alongs that are just getting started are:
Knit So Fine knit-along, based on patterns in the new book by Lisa Myers, Laura Grutzeck, and Carol Sulcoski
Inspired to Knit knit-along, based on the new book by Michele Rose Orne
Double Stitch crochet-along, based on patterns in the new book by Erika and Monika Simmons
Check them out and join anytime!