Brett Terpstra has cooked up HomeControl, a method of using web sharing to control the host Mac, using a iOS-like web app interface. You'll need a little command line familiarity to get it running, but it's not too difficult, and if you're really into it you can go crazy and make it do even more. There's a demo movie that will give you a taste of what it's like.
See also the Macworld article about HomeControl.