Non-Profit Organizations

I'm very interested in starting, working for, and supporting non-profit organizations. I know an 18-year-old that started one on her own, so it can't be all that difficult. But if I could find an established one located either in Houston or with the motivation to start a chapter (right word?) in Houston, I'd be thrilled.

I'm very interested in the following:

community centers for kids
adult literacy
english as a second language tutoring
literature groups for not-usually-into-literature-groups-of-people
teen homeless shelters (i know these are in houston)

Can anyone point me to Houston-area groups for these services?

Thanks guys!
Sarah