Yeah, that's a bit of a bug with OSx86. However, you can manually edit the information displayed in "About this Mac" by editing an Info.plist file (can't remember where it is located at the minute - however, I'll find out for you and let you know).
At the moment the internet is down and I am using the neighbor's connection on a notebook. It's one of the wallapers the comes with Mac OS X 10.4 Tiger and I'll have to upload it when the internet comes back. I have no idea where to download it.