I am doing the MS readathon, where I read books, and need to get sponsors, all the money goes to Multiple Sclerosis research ect.

I was wondering IF I am allowed to ask for sponsorship on the forums, and in which forums would be the best to ask?

I'm not sure if it's okay or not, but it seems like something that would fit best in your own journal (or on outside sites), which you'd link to. Signatures work well for this sorta thing.

I'm pretty sure it is. There was a billboard a while back asking for pledges to a fundraiser-type event in Alaska, and that was never shut down or anything. You could do a billboard too--it'll get seen a lot more than a journal or in your sig unless you post a lot.