A while ago I mentioned VideoSpec which is an app that will tell you all sorts of interesting things about video files. I used it to compare some video I made for an old tv station's equipment to some that they had that worked for their system and find out what was different.
Well VideoSpec is still great but it hasn't been updated since November 23rd 2009.
A friend tipped me off to MediaInfo which is very similar to VideoSpec only it's newer and also FREE.
You can check it out here.