I was going to suggest PCAnywhere (from Symantec) - albeit at a price. But on having a shufty around I came across this comment, which may be of innerest;
"I first installed this software (PCAnywhere) on windows 2000, and it allowed me to work at home for the first time (on a Virtual Private Network) - I was very impressed, despite some problems with the mouse wheel, and system keys like ALT+Tab.
However, after installing XP, I found the built in remote-desktop to be far superior, and I have not used pcAnywhere since."