As a follow-on to my post on the remote access tool GoToMyPC, I recently discovered another service called LogMeIn. This service provides similar functionality, but has a free subscription option (a price most people can live with). The free subscription does not allow file transfers, remote sound or other bells and whistles found in the premium subscriptions, but does provide basic remote control options. Here's the service comparison page on the LogMeIn web site, which provides a detailed breakdown of the functionality offered through the free and "pro" versions of their service.
During the past few weeks, I've had the opportunity to use LogMeIn extensively -- remote controlling a client server -- and found it to be reliable and easy-to-use. In all cases, I had good bandwidth available, so I can't speak to its performance over lower bandwidth connections. That said, if you're looking for a quick and easy tool to provide basic remote control of either a desktop or a server, you should give LogMeIn a look.