Don't know if you figured it out already, I just discovered this post, but if you have a MIDI recording in GarageBand all you need to do is press Print, and it should let you print the sheet music.
You need to have the notation window visible, and not the "Piano roll" window.
My newest tutorials:
Pentatonic Speedster
Funk Lick Library A2
Bat Country
Funk Lick Library A1
Tapping: Level 4
Tapping: Level 3
Alternate Picking: Level 2
Find all of my lessons here:
Complete Lesson Catalog
Pentatonic Speedster
Funk Lick Library A2
Bat Country
Funk Lick Library A1
Tapping: Level 4
Tapping: Level 3
Alternate Picking: Level 2
Find all of my lessons here:
Complete Lesson Catalog