Always have a contract. Although the following might not pertain specifically to a TOS, there are some wonderful sites for information and/or learning how to do various contracts. No doubt they will come in handy at some point.
Website Planning Worksheet
Web Site Development Agreement - Example
The Geek's Guide to Internet Business Success
Hiring a Site Developer
A Merchant's Guide to Opening a Store on the Web
Research Report: The Real Estate Industry and the World Wide Web
Ars Digital - For various reasons, this should be Bookmarked--forever
Developing Effective Contracts
Web Site Development Agreement - Website Design Contract Form
The Jurifax Store
Web Developer Contract Swipe File
E-Sign Is Law, But Is It Safe?
An example of a non-disclosure agreement can be found here:
standard advice (get a lawyer, etc.) applies...