Try OxyClean
The For the future you may want to check out the Leg Shield Shield. It is a neoprene leg strap that prevents the bike grease from getting on your pants. I use it for commuting. Great solution.
See it here.
http://www.amazon.com/Leg-Shield-Revolutionary-Bicycle-Strap/dp/B006J0PHAI/ref=sr_1_20?s=sporting-goods&ie=UTF8&qid=1324073135&sr=1-20
