Actually the ii-V-I progression is probably the most popular chord progression. In the key of Bb we must know the harmonized scale, usually the Major scale but could be any scale which are created usually by stacking diatonic 3rds. So in Bb the ii is Cm, the V is F7 and the I is BbMaj7. MIDI software makes things easy, but it really helps to understand basic music theory. Jimmy Webb's TuneSmith is an excellent read.