Sledge
If you have windows xp pro you could simply use the built in remote desktop connection software that is in the OS, I use it all the time for work and fixing my wife and my mothers computers.
The problem with the remote desktop is that you require good security set up and also you will need a permanent internet connection.
There are loads of other bits of software out there but a good one that gets round the need for opening firewall ports etc. is a product called
gotomypc which is web based. You can test it free on the site. It's probably not the cheapest solution but it works fantastically and you can get a free trial (I think)
Let us know what you end up trying.
FSD