Verified answer

Instant House call http://freeremotesupport.com/

CrossLoop http://www.crossloop.com/

TeamViewer http://www.crossloop.com/

I would go with Instant house call or team viewer because I don't remeber if you can control another computer with crossloop

Edit: Your friend will have to have XP Pro or Vista business or Ultimate in order to use remote desktop. And you friend would have to have their computer plugged in directly to their modem in order to use Remote assistance.

I have two sites that i swear by, the first is www.gotomypc.com they give you a free 30 trial, and the second one is www.logmein.com and its totally free.

If you have windows xp, it comes pre-installed.

If you have something else I think it'll cost ya.

control panel, remote access...