This is a great example of a ii-V-I tune:

For example, in the chord changes Boo posted:

Verse 1:

I - vi - ii - V
Eb6 - Cm7 - Fm7 - Bb7

F: ii - V Eb: ii - V
Gm7 - C7b9 - Fm7 - Bb7

I - I7 - IV
Eb - Eb7 - Ab

ii - V - I - vi - ii - V - I - vi - ii - V
Fm7 Bb7 Eb, Cm7, Fm7, Bb7, Eb, Cm7, Fm7,Bb7

If the song is memorized by the numeral method, and simply a series of ii-V-I chord progressions, it becomes a lot easily to memorize and play in other keys as well.

Scott