VideoLAN’s cross-platform media player, VLC, has finally been released as an iPad app at the App Store. The app allows playback of video formats outside of Apple’s normal MPEG-4/H.264 combination. Most publicly available codecs should be supported, such as AVI. Sadly, the the iPad version of VLC can not play high-bitrate MKV files, as the iPad is too slow to run them at full speed.
VLC is a free 8.9MB download.