Media Conversion

[Craig]

We have a web site where users can upload media files to their page
they are creating. When they upload the files it seems logical to
convert them to some kind of common format, probably WMV for Windows
and Quicktime for MAC so that everyone can view them and they can be
easily streamed by people viewing the page.

I am looking for recommendations on software that can do this
conversion process keeping in mind that it needs to be called and run
on a server, possibly run as a service or called at a command line to
do the conversion process. There are many programs that do media
conversion but they seem to focus on end user tools, not server tools.

Craig.