You could try "Zamzar" which is a free online video converter... additionally, this windows 7 video converter http://convert-video-dvd.com/video-converter.html#135 is also not bad, it let you set the video aspects, resolutions, bit rate ... more important,
No asynchronism in video & Audio !!!
I got a Flip Ultra HD for Christmas. The only problem is, it saves the video as .MP4. I am able to drag the mp4 into Movie Maker and edit. But if I publish, it distorts the sound and makes the audio not in sync. Is there a codec I need to install to make this work? Even if I convert the mp4 file with software, it does the same thing. I am running Windows 7 on a Dell Studio 17.