have you seen this site Donors Choose? it's really cool! it's for schools. i wish more schools and more areas were involved in it. essentially, from what i can tell, teachers submit proposals and they get posted to the site. you can donate some or all of the amount to cover whatever it might be.
one of the choices is for doing art in elementary schools. many of them are for title 1 schools in very low income areas. i think it's pretty cool. one teacher in the bay area wants to make scrapbooks with her students b/c she realized that many of them don't HAVE pictures of themselves!! how COOL is that?