Log Me In
Log Me In is a very handy program - once installed on a PC is allows any other PC with a web browser to remote control that PC. Now there are already solutions to do this already, such as Remote Desktop or WinVNC.
Remote Desktop is a Windows function that enables a network user to log on to a remote PC. The thing is, it logs off the current user of that PC and only works over a network - even then it isn't guaranteed.
WinVNC is a server that runs on a PC, so that any browser connecting to a certain port on that PC can remote control it. Unfortunately one needs to know the IP of the PC, and should the PC be behind a router ports must be forwarded. So it isn't exactly easy. Even when it runs it can be sluggish and looks a bit crap.
LogMeIn runs at startup and signs onto an account - the account owner can access the site through a browser and see which PCs are logged in. Clicking on the PC name and entering a security code (or Admin password) allows access to the file system, and to fully remote control the PC. I've installed this on my girlfriend's laptop so that I can do tech support without having to use the phone.
Incidentally I installed it on my own PC, then tried to remote control it, from the same PC. Here's the result:

Ooh, I feel dizzy now - but you can see that this program is very cool.
- Link to LogMeIn
That is awesome...but my eyes are still trying to recover. :)
Nice to see you on the site Ryan, I wonder what that picture would have looked like on a 42" Plasma screen!
Heh, just found this by fluke and i just thought it was weird. I also have been using LogMeIn for some time and it is a good bit of software. Very useful.