My DD, Karen (krnb on the boards) went to Russia as a sophomore in HS about 11-12 years ago with the People to People program and we/she thought it was great. It is expensive, and there were fundraisers and sponsorships that some kids undertook to help defray the expenses. Some kids got sponsorships from the local VFW, etc. and the repayment was for the student to come back and spend an evening talking about their experiences, etc.....so that added to the overall experience. Also, depending on the type of work each student puts in, there can be transferable college credits obtained from the U of Washington. Karen earned about 5, I believe.
I've heard of People to People having trips from junior high aged kids, but I don't think, knowing what I do about the program, I would want my child that young going. However, I would HIGHLY recommend it, if the program is still the same, to any responsible HS student. The time each student spends with the families and people of that specific country really aids in helping international understanding from both sides of the ocean!
I would certainly be happy to answer any questions you might have.