I've shared this with a few people and thought I'd share it more widely. Two years ago my school came up with a social networking policy for faculty and staff. This gives the adults in our school clear guidance about what is expected of them. If you use it, please credit it back to The Hewitt School. We fully expect this policy to evolve as our online lives evolve. This just happens to be where it is right now. If you're looking for other policies Alex Ragone recently shared this link, which has quite a lot on it. We've been thinking about this more and more as our school just launched it's official Facebook fan page.
Policy on Social Networking
Faculty and staff members are only to interact online with students in school-sponsored "spaces." Interactions on CourseWeb, Hewitt e-mail, and other Hewitt-sponsored online spaces are appropriate, while interactions via commercial sites such as Facebook, MySpace, etc, are not. If a faculty or staff member is contacted by a student via non-Hewitt channels, the corresponding division head should be notified.