Rules & guidelines -- the workplace is full of them. Maybe that's why the majority of employers have taken so long to develop a social media policy. Perhaps they don't feel threatened by it, or aren't familiar with it at all.
From bashing the company to workplace bullying, it is proving to be an HR issue that does need addressing. This article from TheNextWeb.com is a simple summary of procedures that you may find helpful as you get started:
Recent NY ruling alerts employers about social media policy
You'll also find books that present a more internal view of social media for business organizations, such as Smart Business, Social Business: A Playbook for Social Media in Your Organization by Michael Brito.
Has your company developed a social media policy?