Mediacleaner if you want to spend some cash, or even good ole Windows Media Encoder..
They'll both do the job, but obviously mediacleaner will have more bells and whistles. There's some other ones, like virtualdub as well that I know nothing about.
http://www.mediacleaner.com
http://www.virtualdub.com
http://www.microsoft.com/windows/win...ad/default.asp
Cheers,
Jason
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