Don't think this was posted here. If so, ignore. But, I think this is a super great cause.
(sorry, on iPad and can't make clickable)
To sum it up: have your child write a letter to santa, put in envelop and stick stamp on it, put it in the 'red box' located in any Macy's and they'll send $1 to make-a-wish for every letter up to 1 million.
I'm gonna do it with my daughter. She'll be excited that "Santa" will get her letter, and it's for an awesome cause. I keep seeing it on Good Morning America, and meaning to post.