ITManagerToolkits.com has uploaded a Social Networking Policy PowerPoint to the Knowledge Network. This electronic presentation explains what should be included in a social media policy specifically addressing Facebook, Twitter and blogging.
For instance, this presentation suggests that employees who use Facebook should help promote the company if they are using the Web application on company time. In addition, such a policy should encourage uploading pictures of company events, but require that a manager sign off on posting those pictures.
Not all social networking policies have to be alike, though. Check out The Greteman Group's Social Media Policy, also in the Knowledge Network. Also, blogger Daniel Hoang contributed a Sample Social Networking Policy. The bottom line is to give employees a way to promote your company using social networking, but put guidelines in place so that they do not abuse it.