You can also add this to your registry. BlueZX3 turned me on to this some time ago. Just unzip, and double click. It adds an option to the context menu, when you right click on a DLL to either register or un-register it. Alternatively, you can just double click a DLL and it will register it as well, with the standard "DllRegister Server in C:\blah blah file.dll succeeded" pop-up dialog.
It works in batch as well, when I copy my RR folder to the car, I do a search on the RR folder for *.dll. I then select all files, and right click on one of em and choose register. If there are a lot of dll's it will warn you it may take a minute
I have used it on XP Pro, and recently found it also works on Vista.