I have belonged to groups/clubs at LQS and another at Hancocks and a Guild in a church. A Guild will charge dues and have officers, etc.; a club is without dues and the members generally help each other with quilting techiniques, etc. I would contact a quilt shop or other sewing store in your immediate area first. Lot of times, they like the walk-in business and what quilter does not buy a small item when around fabrics? lol Anyway, starting a club can be as simple as putting an ad in your local newspaper or maybe flyers in the window of the fabric shop. It is amazing the number of ladies and some guys who will join. As for fabric....well, once the word is out about your charitable group, quilters seem to donate fabrics they do not want and estate sales are super. Check out the goodwill and salvation army shops on a regular basis. It will not take long before all that one needs to provide is the batting.
Also, I am a Project Linus blanketeer. Why don't you start a Chapter in your area. No dues and so much good is provided to children in hospitals and in our immediate case, blankets for the Joplin, Missouri victims.
Here is a link to the national office of Project Linus so you can see what is involved. Thank you and good luck!
http://www.projectlinus.org/