I'm not sure exactly where you live, but here are a few suggestions:
Project Linus:
http://www.projectlinus.org/voluntee...tateKey=CA#tgt
Project Linus donates quilts to children in crisis, Homeless shelters, Hospitals, etc. The above link lists chapters around the country.
Quilts for Kids:
http://www.quiltsforkids.org/
I don't have any personal experience with this charity.
Here's a list of other possibilities posted by QuiltersWorld magazine:
http://www.quiltersworld.com/makeadifference.php
If you can't find what you're looking for in any of these links, try googling Quilt Guild and the city you live in. You should be able to find out about national or local organizations that collect quilts for charity.
If you just want to do something on your own, you can always contact a local Homeless shelter, Women's shelter, Public Hospital, Head Start program, Police Department, Fire Department, Nursing Homes. I'm sure you can find a worthwhile charity interested in putting your quilts to good use. You can also contact the Band Directors from your area High School to see if they hold any Silent Auctions or Raffles where they might be able to sell a donated quilt as a fund-raiser. I made a t-shirt quilt for my school's band and they sold it for about $550.00.