what exercises can you do to tone your obliques?

Twists, oblique crunches, hanging oblique crunches, twist sit ups, weighted side stretches.

This is old fashioned but effective.
http://orgs.jmu.edu/strength/JMU_Summer_2000_WebPage/JMU_Summer_2000_Sections/15b_Summer_Core_Series_Obliques.htm

here's some more, basicly the same as already posted though

http://www.bodybuilding.com/fun/exercises.php?Name=Dumbbell+Side+Bend

If you know how to slip a punch, just do that side to side really fast until you feel like your waist is on fire.

Tyson used to do it.