Apple ipod

What video formats supported by iPhone?

So I'm sitting here in a library for Matroska video files. I want to convert to put it on my iPhone, but I have no idea what video format compatible with iPhone. 3gp seems a bit old school for my purposes (resolution sucks). Some advice please!

iPhone only supports MP4 and H.264 video, if you want to know how to convert a video and put DVD movie on the iPhone, I think this step by step guide to help

First iPhone 3GS video sample example