Check out Shredder, Splashtop 2, and other music-related apps right here: https://www.sweetwater.com/shop/ios/apps.php
Mitch tries out the Shredder guitar-to-MIDI app, which lets you play synthesizer sounds via your guitar with no additional MIDI-converting hardware required. It also lets you save your performance as a MIDI file for use in your DAW or sequencer.
Splashtop 2 is a cool app that gives you control over your Mac, perfect for remote control of your DAW software. Since it’s basically showing you the same thing as your computer’s monitor, you don’t need to set up or assign any controllers.