I know most foreigners use vpn to get facebook and other sites. I just read that vpns may be illegal. Is this true? and if not.. what is a good one to have?

You may want to read this forum thread:
www.gokunming.com/en/forums/thread/3238/vpn

lots of things are technically illegal in China. There is probably a law in the books against breathing without permission (maybe even a law against polluted air). But as you see, many laws only matter when Beijing decides to enforce them.

We have it pretty good here. A couple of years ago, Malawi outlawed the release of intestinal gas.