Hi Nick, Glad you had a great run around the apple isle!
Best free program to use is something like Free Video Coverter http://download.cnet.com/Koyote-Free-Video-Converter/3000-2194_4-10805335.html?tag=main;dropDownForm (click the direct download link).
Then convert it to a format such as MP4 (MPEG4 codec), ensure the size is appropriate (IE HD 1280x720) and FPS is 25-30. Play around with the bit rate to get the quality right.
You will need to stuff around for a while to find the right ratio for size vs quality, but then the file should only be a few 100 Mb at worst.