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
http://www.wilsonweb.com/worksheet/pageplan.htm
Web Site Development Agreement - Example
http://www.briantaylor.com/websitecontract.htm
The Geek's Guide to Internet Business Success
http://provider.com/
Hiring a Site Developer
http://hotwired.lycos.com/webmonkey/99/22/index4a.html
A Merchant's Guide to Opening a Store on the Web
http://www.dpro.com/dpro/center/survey.html
Research Report: The Real Estate Industry and the World Wide Web
http://haas.berkeley.edu/~creue/realweb.htm
Ars Digital - For various reasons, this should be Bookmarked--forever
http://arsdigita.com/
Developing Effective Contracts
http://designwise.net/webdesigner/contracts.htm
Contract Monitor
http://www.gag.org/contracts/contracts.html
Web Site Development Agreement - Website Design Contract Form
http://www.briantaylor.com/websitecontract.htm
The Jurifax Store
http://store.yahoo.com/jurifaxstore/
Web Developer Contract Swipe File
http://provider.com/contracts.htm
E-Sign Is Law, But Is It Safe?
http://www.wired.com/news/politics/0,1283,39172,00.html
An example of a non-disclosure agreement can be found here:
http://www.bitlaw.com/forms/nda.html
standard advice (get a lawyer, etc.) applies...