Hobbyist Software Limited has VLC Streamer (iTunes Link) for the iPad in the iTunes App Store for FREE (regularly $1.99) for a limited time.

Sit anywhere in your house and watch movies or TV shows on your iPhone, iPod or iPad.
VLC Streamer streams movies from your computer to your iDevice. Winner *Best Entertainment App* Chip.de.

You can watch anything from your movie collection. No need for complex conversion processes. No need to manually transfer programs to your device.