I think you have your terms mixed up a bit.
The Pod 2 is a multi-effects unit and the midi interface is for patch changes using either a remote midi pedal or a computer playing a midi sequence with patch changes programmed in. In other words, if you're playing back a midi song on your computer, you can set it up so that one of the midi channels will change patches for you automatically as you play.
Midi recording on the other hand, is usually done using a keyboard or a guitar synth and involves recording notes to the computer almost like notes on a piano roll.
When you play the midi file back, you can plug it into a midi instrument so that it will play back using whatever sound you want.
Of course it's way more involved than that but those are the basics.
