snappymaths.com
sheppardsoftware.com
LOTS of different multiplication games
Multiplication Games
Multiplication & Division
ABCya.com
Education.com
Filter by Grade (on left)
Brain Pop.com
LOTS of Multiplication Games
Fun For the Brain.com
abcya.com
(similar to Bejeweled, but incorporates multiplication)
Task Cards or Scoot Game
NOT Free
(but maybe you can make your own)