I don't have much experience with this myself, but I've looked into it, and I found the following questions helpful (although you may have already seen them):
Also the Wordpress TOS is licensed under Creative Commons and seems to be a popular one to use as a template/base for your own.
I don't see anything wrong with using one of these templates to start off with. However, once your product starts getting some traction I would definitely have one drawn up for me by an attorney.
Hope this helps!