Gmote turns Android into a remote control for a computer, allowing users to run movies and music at a distance. It supports all of the standard remote control features such as play, pause, rewind, volume controls etc. It also has a built-in file browser that lets you select what to play.
Also has a laptop pad sort of option, which is great for presentations etc. The file is actually really small so its useful to keep it about even if you dont use that often. No updates are required anymore as its finalised i believe, as stable as it can be. Which is a plus!
More info here - http://www.gmote.org/