thechar software
BPM: beats per minute
iTunes allows you to specify the beats per minute (BPM) but it is not easy to get that information. There is software that will analyze a song and determine the BPM but the software is complex and not always reliable. The simplest way it to listen to the song and tap out the beat. BPM Graph will determine the BPM based on your taps. It shows the average BPM of the last 4, last 16, last 32, and all taps, and a graph of these averages showing how they varied over your sample.

BPM Graph iPhone App
BPM Graph helps you figure out the beats per minute of a song that is playing. I am building an iPhone application that will assist you to determining the BPM of a song. You can see some screen shots of the application.
You can get the BPM Graph iPhone app here.

iPhone App Documentation
The app has three help files:

Web version
I created a web version of beat counting in JavaScript for my wife. You can try it here.