If he has XP and you have XP just do this...
Control Panel -> System
go to Remote Tab
Turn on Remote Desktop.
Then, go to Start -> Help -> "Invite a friend to connect to your computer with Remote Assistance"
The screen will then direct him to either IM you (via Windows Messnger) or email (via Outlook) and it will send an invite to you. It even sets everything up in terms of firewalls and everything. MUCH MUCH easier then VNC for newbies.
Also, in the Remote Tab, it lets him configure how many days the invite is still available, such that this is not a permanent thing.