Software/Web Application Development Contact

Hello,
I have not been in the freelance business long and I am already having the "We never agreed on that" customers. I am looking for a nice FREE contract which i can use so before I start anything I can get everything down on paper.

Is anybody prepeared to share there contract so I can take a look at?

P.S. Signing contracts when your an internet freelancer is not easy or instant is there anyway I can make the contract stand up legally without a signature? You know like the websites where they have checkboxes saying "I accept, and understand the agreement"?