TeamViewer, any VNC software (I suggest the ones using Tight Encoder), Remote Admin,
www.google.com ;) Depending on what you want to do with it ( just remote control, file transfer, etc.) they are all good. Me, for instant, I use tightvnc for viewing and Radmin for file transfer. Hope it helps.
@DomainBroker: perhaps he just don't want to spend money and then discover that he could have used a free software.