All-Star mini Crostics: Over 100 puzzles in a java applet. New puzzles added semi-weekly.
CRpuzzles: Over 100 mini Crostic puzzles.
JGames: Over a dozen puzzles in a java applet.
Puzzability: A sample interactive puzzle.
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.