Any High-school Travel Grants Available?

I really would like to go on a trip with Global Leadership Adventures (GLA) to Africa the summer of 2012. Through the duration of the trip, the group will help with global relations, poverty alleviation, children issues, environment issues, etc. So not only will the trip benefit me, but other world-wide. However, the trip does cost a relatively large amount of money, and I do not know if I will be able to go because of it. So, I was wondering if there are any scholarships or grants available for me to go on a communitarian's trip to Africa. I am going into 11th grade next year, do well in school, and already beginning to do community service through my hometown. So are there any chances, that there is a grant/scholarship for me out there? Thanks! :D