I've used microsoft's rdp. It's simple, and has the advantage of being accessible in any winxp pro.
I could set it up in my local lan, but couldn't set it up on the internet (i didn't bother to find out how to configure my router for that).
But there's a problem with that protocol: IIRC, as soon as the remote user logs on, the session is terminated for the local user.
Also, i think that vnc might be a better option, as it allows you to access your computer through a browser window, and i think it is faster.