Free WebM Encoder is a simple utility that lets you convert your video files to the new WebM format. The program has an extremely easy-to-use interface. Just add the files you want to convert to the list (you can drag and drop them directly from Windows Explorer) and click the convert button. A variety of video formats can be converted, including AVI, MP4, FLV, WMV, and MOV.

What is WebM?
WebM is an audio-video format designed to provide a royalty-free, open video compression format for use with HTML5 video. The project's development is sponsored by Google.

A WebM file consists of VP8 video and Vorbis audio streams, in a container based on a profile of Matroska.
Although the project releases WebM related software under a BSD license and all users are granted a worldwide, non-exclusive, no-charge, royalty-free patent license, some in the industry have called upon Google to provide indemnification against patent suits.

Home Page - http://webmsoft.com/free-webm-encoder.html