Video Converter for Mac download at Video Converter for Mac
is specially designed conversion software for Mac users. It can perform video and audio conversions and extract audio from video files. It features powerful conversion function and can convert almost all popular video formats to AVI, MP4, MOV, MPEG-1, MPEG-2, RM, VOB, WMV, BlackBerry MPEG-4 video(.mp4), BlackBerry 3GP video(.3gp), BlackBerry AVI video(.avi), etc. It supports iPod, iPod touch, Apple TV, PSP, PS3, Zune, BlackBerry mobile phone, Archos, iRiver and Creative Zen etc. It also support audio output formats as MP3, WMA, OGG, AAC, M4A, WAV, AC3 and and BlackBerry AMR audio (.amr).

The key features of this excellent Mac conversion software includes:
1. Support Multithreading and batch conversion and Intel Core 2 CPU and provides >200% converting speed.
2. Provide several optimized profiles for iPod, Apple TV, Zune, PSP, PS3, BlackBerry mobile phone etc with different quality which can be used directly without any further settings.
3. Newly added feature of supporting BlackBerry MPEG-4 video (.mp4), 3GP video(.3gp), AVI video(.avi), and BlackBerry AMR audio(.amr).
4. Support plentiful formats.
5. Support trim function for video and audio clip.
6. Provide both default settings and professional settings for users.
7. Support snapshot in preview process.
8. Newly added iPod touch profile.
More info at Video Converter for Mac

It seems Not an easy task to find a working converter for Vista! Did a quick Google, and of course about 300 programs popped up on some suspicious sites.
But I really need to convert a few protected iTunes videos. I tested a couple of sites and detected MelodyCan converter. Their free trial is quite impressive and allows converting video and audio formats both protected and standard ones. The main requirement is the ability to play the original file in Windows Media Player (for WMV) or QuickTime Player (for M4V). Their URL is MelodyCan: Convert Any Purchased or Copied Audio and Video Files, Audio CD Ripper, YouTube Ripper Plug-in