Have never used it with a MAC only a PC....having had a quick read it doesn't look like it is MAC compatible. You'll need to have a look for a similar programme for MACs. quick trawl through a forum has uncovered this one for MACs but have never used it.
If you are converting from a copy-protected DVD, you can first use Mac The Ripper to copy the DVD to your hard drive while simultaneously removing Macrovision protection. Then run Handbrake to convert DVD to the ipod-friendly mp4 format.
Be warned that whatever method you use, you can experience issues with the dubbing. About 1 in 3 of my converts had the dialogue about a second or so out of tune with the video.