IBM has issued guidelines for its employees who are on Second Life. Keep up the corporate image, don't do nasty or bad stuff -- pretty much what you'd expect to protect the "brand."
And touches in a 21st-century way on issues raised by the book Speechless: The Erosion of Free Expression in the American Workplace, by Bruce Barry. I'll be interviewing Barry on Aug. 24 in New York for Bill Sobel of NYMIEG, with whom I'm partnering on a few other things.
I'll ask Bruce about all the difficulties of managing "real" vs. worklife, for both employees and employers, and how to manage the issues in a virtual as well as real world. Believe me, you wouldn't believe some of the things people are fired or reprimanded for and how little protection of speech there is. You also wouldn't believe how difficult it'll get to manage the situation as an employer if Bruce's book and campaign manage to move the needle.