I don't think that would be possible unless a piece of software estimated it from trying to recognise the beat in music. I'm unaware of any such feature in iTunes but any software that could do this would likely be fairly unpredictable except for the simplest songs. I've noticed that the iTunes visualiser isn't particularly good at recognising the speed/tambre of the music (nice effects though).
If it were MIDI format, it would be easy, as the tempo is recorded in the file format, but this is not the case with waveform audio formats such as MP3, AAC, AIFF, WMA, WAV, etc.
I'd like there to be an update to iTunes so that it would just offer options such as "Slow", "Medium" or "Fast", or a simliar such system, instead of BMP. As it stands I don't use the BMP feature because I don't know the BMP for any of my songs either!