All-Star mini Crostics
Over 100 puzzles in a java applet. New puzzles added semi-weekly.
JavAcrostic Cafe
Classic puzzles by Middleton, Wortman and Kingsley.
Sloth2toed
Interactive version of puzzle by Underwood.
Sue Gleason's
Java applet updated bi-weekly, registration required. Subscription needed for daily solving competition, archives and puzzle creation software.