We use PTOToday's Volunteer Builder, but for some events we also use SignUp Genius (www.signupgenius.com). Volunteer Spot and Sign Up Genius are really great for room parents to use to coordinate class parties and events like that, too.

SignUp Genius and Volunteer Spot are very similar, but parents seem to have an easier time using SignUp Genius.

I posted last year asking for a website that helps to coordinate volunteers. I ended up using volunteerspot.com. It worked great.

Thank you to the member that recommended it.