i went with an organisation called VSN who are part of a wider organisation called GVN. This is a very worthwhile organisation where you can really get involved, it is well run, and the programme fee, which is lower than any other i have seen elsewhere, is put to good use, every penny of it!
www.gviusa.com/ Choose from Teaching, Orphanage & Healthcare volunteer projects
www.volunteerhq.org/ American volunteers wanted for affordable volunteer trips abroad!
www.volunteeringsolutions.com/nepal Orphanage, Teaching, Summer Program Volunteer in Nepal - starts $200
www.crossculturalsolutions.org/Asia 1-12 Weeks in Thailand or India. Help People and Change Your World!
www.feedingdreamscambodia.org/ Help educate the poor of Cambodia. A life changing experience.