If you don't know what is FFMPEG... you possible don't need this.
Or can check out http://ffmpeg.mplayerhq.hu/
But really, originally written for Linux it's hard to find fresh Windows binaries. It's possible to build it, using MinGW and MSys.
I'm posting my 23 august build:
build_08_23_08.zip (4,14 mb)
But it was sad build, it still does not encode to h264 (mp4). If someone knows how to build it with such support, please let me know.
Added:
Build with libx264 and even makes h264 videos ( some troubles with bitrate, but I think minor )
ffmpeg_13981.zip (6,26 mb)