Just in case some of you have this available, it was signed and made permanent. Previously it was set to expire in 2010. Prior to the signed bill, the cost + the potential expiration made a lot of employers reluctant to offer it. If not, you may want to consider suggesting it to the powers that be. Could be a good deal for some people here, depending on your tax bracket or maybe if you have some crappy 401k offerings.
Decent website about it. Lots of info out there if you google "Roth 401k."