Zamzar (online video converter)

Zamzar.com
gets my vote as the best choice for online video converters. All the
online solutions work in about the same fashion. They all have ads on
the pages. They all upload your file to their server,
allow you to choose an output format, and then provide a way to get
your file when the process completes. One particularly handy feature of
Zamzar is the ability to grab a video from a URL and convert, so if you
upload videos to a directory or find something on YouTube, you can
covert the videos without downloading them to your computer first. Limitations for the free version of Zamzar are 100MB file sizes and no more than 5 concurrent conversions.