How to use Windows XP to remotely control a Vista machine?

I need to help a relatively non-IT literate friend configure various settings on their Vista machine. We have a Mac and an XP machine. I gather I can use Remote istance to do this but don't know how to explain to him on the phone how to configure his Vista machine to allow this. According to a page I found on the Net, he needs to Open Remote istance by clicking the Start on, click All Programs, click Maintenance, and then clicking Windows Remote istance. But he tells me 'Maintenance' isn't an option under 'All Programs'. Can anyone guide me in helping him request remote istance from me so I can view his screen and guide him on the phone?