For a streamlined wireless mouse and keyboard solution, Remote Droid is remarkably user-friendly. I had fairly low expectations because my experience with apps like these has been less than stellar, but this open-source, cross-platform wireless touchpad hits it out of the park. To get rolling you have to install two elements: a java-based server client for the computer-side and then the RemoteDroid app for your Android phone. The system utilizes your wireless network to communicate between the server-side and your phone. While this may seem like a pointless toy, I often find myself moving around from laptop to laptop at my office with little to no notice for impromptu presentations and meetings. This app provides a handy wireless mouse on the fly.
A video demonstration of the system in action: