Does anyone know how to remove grease stains from pants? Any help would be greatly appreciated!

Have you washed them yet? If not then using one of those Stain Sticks can do wonders. Here's ideas for other products you can use:
http://housekeeping.about.com/od/productreviews/tp/stainremovers.htm

Here's the source my wife uses:
http://ohioline.osu.edu/outside/stainrem.html

... and there we're told

"Oil stains can be removed by pretreatment with a heavy-duty liquid detergent, an aerosol petroleum-based solvent pretreatment spray, or a pump-type detergent-based pretreatment spray. If these products are unavailable, you can use a powdered detergent that is mixed with water to make a runny paste and apply that to the stain.

The heavy-duty liquid detergents or aerosol sprays are more convenient and effective. Work the full-strength heavy-duty liquid detergent into the stain or spray with the pretreatment product, then wash the garment using hot water (if safe for fabric), the recommended amount of detergent for a regular laundry load, rinse, and inspect before drying. Repeat this treatment if removal is incomplete the first time."

Hope this helps!

Thanks for the advice!:)