I bought quicktime pro thinking it would do this but I think it only converts files FROM mp4 TO other formats and not vice versa.
QT 7 Pro keys the QT 7 Player for editing and the transcoding of file formats which are compatible with your systems codec component configuration. It does not add any new codecs. Thus, if you cannot play the files in the the QT 7 Player, you will not be able to convert them using QT 7 Pro.
I have edited a bunch of home videos on a PC so that they are wmv and avi files. Now that I have an imac I would like to be able to watch them on the imac and on my appleTV. How do I convert these files?
There are many solutions here. For QT 7 Pro to convert from WMV to TV compressed files, you need the Flip4Mac WMV export codec (minimum of $29) installed on your system. For most AVI files, you would need the Perian component package installed and ensure that there are no component conflicts. If you don't are whether you use QT 7 Pro or not, the any number other work flows are possible—FFmpegX (shareware), Visual Hub (unsupported), HandBrake (free), etc. Of those mentioned, I would probably prefer HandBrake. Since it contained its own open codecs, you don't have to pay for a codec (Flip4Mac) or worry about component/app/system conflicts (Perian), and it has specific presets for both TV and TV2 exports, as well as, allowing you to create your own custom export preset(s).