A google search led me to this site with some interesting volunteer programs:

Teach English to Buddhist monks: http://www.volunteeraidnepal.org/monastery/

Teach computer skills to children: http://www.volunteeraidnepal.org/programs/volunteer-projects/computer-education/

There are a bunch of other volunteer programs listed on the left side of the page that might appeal to you.

I hadn't heard of the organization prior to this search nor do I know much about the founders, other than  what is mentioned on the site but if you are planning on travelling  to Nepal and spending some time there, you may not have much to lose in giving them a try.

Good luck!