I have a Mac Mini that I purchased to code my iPhone app. I only used it for the iPhone development, so I currently have it hooked up to my living room LCD TV so that we can watch internet TV (if we miss an episode due to the DirecTV DVR’s being all booked up on Thursday nights) and to watch Netflix instant downloads, etc. I had been using a wireless mouse and keyboard until I searched the iPhone App Store and found an app called Wifi Touchpad by MB PowerTools. Edit: See update below, found a better app, Air Mouse! This app works amazingly! You can replace both mouse and keyboard functionality via wifi. For a mouse, your iPhone screen becomes a touchpad. You drag your finger around to move the mouse instantly, no delay. Tap the screen or tap the simulated mouse buttons to click on items. Tap an arrow to bring up the keyboard. There are a few other features that I haven’t used yet, but the mouse and keyboard worked perfectly. You do have to download and install a free “service” application to run on your Mac to talk to the iPhone app. Just set the app to run when your user account loads and you’ll be good to go anytime you want to control your Mac from the couch.
Update: Air Mouse is an even better app! I recommend watching the video, this app is incredible.