Remote desktop

I have just discovered the joys of remote desktop in my home network! I am regularly tasked with fixing my father-in-laws PC for very minor things. I was wondering what it would take to be able to use RD to access his system? I need to run adware and clean up and stuff like that.
What does it take just in general to connect to someones comp?

He has verizon FIOS and hes behind a router......

 

To set up his computer, see:
http://www.onecomputerguy.com/networking/xp_remote_desktop_host.htm

To set up yours, see:
http://www.onecomputerguy.com/networking/xp_remote_desktop_client.htm

 

How do you do this in Vista?

 

For the host:
http://www.onecomputerguy.com/networking/vista_remote_desktop_host.htm

For the client:
http://www.onecomputerguy.com/networking/vista_remote_desktop_client.htm

 

ok srry to bother you again but is it possible for a Vista to XP connection, or a XP to Vista?

 

Yes it is possible.

 

oh ok so just configure the host settings for vista and client settings for XP?

 

My father-inlaws computer is running XP-Home. When I went to his house, the tab for remote only contained the allow remote assistance option the rest was blank. One of these systems needs to be XP pro right. I have that as well on another system.