What legal/tax stuff do I need to consider for babysitting/tutoring?

I plan on starting to advertise my babysitting/tutoring services to my neighborhood. The babysitting and tutoring sessions will be done at my parents' house (I'm still in college and living with them--bummer, I know!). I was just wondering if I needed to take care of any legalities beforehand. Also, it won't be a day care; I would take care of one family at a time.