MediaInfo is a free, open source application that specializes in giving you a complete taxonomy of properties for audio and video files. It has only a 1.3MB footprint--small enough that I carry a version on my pocket USB thumb drive. If you have the Windows version of MediaInfo installed, you can also add it to your right-click context menus so that you can get to the properties of a video or audio file with one mouse click.
For most popular video and audio file formats, MediaInfo will give you general information about a file, including title, author, director, album, track number, etc. You can also get the codec required and bitrate for just about any video file. If you want a higher end, richer product for these purposes, VirtualDub is also free and open source, but it's not quite as quick to get in and out of as MediaInfo.
Are you interested in more on video and audio tools? See my previous post, and Lisa's.
Do you know of any good open source applications for working with video and audio?