Hey that was great! I really like that Pink Floyd song and you did a nice job with it.
Here is something I did in Garageband on the iPad called Sweet Summer.
http://www.soundclick.com/player/single_player.cfm?songid=11595878&q=hi&newref=1
It isn't a slick finished piece like yours. Just a sketch of a musical piece. I didn't use any Touch Instruments as you had done. Just a couple of acoustic guitars and electric bass. The drums were loops to play along with and keep time. No effects, just get it in there before I lost interest.
One thing I wish Garaband for iOS had was automation for adjusting the volume per track throughout a song.