See the support page for video demos and review links.
Video Demo: http://youtu.be/8oQ_mZQvuFc
User Demo: http://youtu.be/kZOqJuR0QKs

Audio MIDI Connect is a revolutionary way to control synthesizers, sequencers, and transcribe music with your guitar, bass, or even your voice. The musical pitch of the live instruments are detected by the app, and translated into MIDI notes which can be sent to external sequencers such as Garage Band, Logic, or Protools, or to synthesizer apps running on the same device.

When converting from sound to MIDI notes, the biggest challenge with both hardware and software methods is keeping the delay between the sound and the MIDI note low, while also having accurate note detection. With Audio MIDI Connect, the pitch detection is fast enough to capture playing at moderate speeds in real time. In addition to the real-time detection, the app can also record audio, and then perform conversion later -- this allows you to capture the exact timings of the playing, along with more accurate note detection, in the MIDI output.

The app supports both Apple Core MIDI, and the DSMIDIWifi standard, making it easy to connect to Mac OSX, Windows, and Linux.

For anyone developing a sense of pitch, the app also provides a visual cue to the note being played -- the display is large and clear, making it easy to see when your device is sitting on a music stand.

★ Upcoming Release ★ An update to the app is nearing completion, and will add Audio Copy and Paste, along with faster and more accurate note detection.

★ A note on background processing! ★ Audio MIDI Connect is compute intensive, and so are many synthesizer apps. Depending on the speed of your device, and the complexity of the synth patch, you may have noise, distortion, or feedback from a synthesizer running on the same device. We have found Alchemy Synth Mobile from Camel Audio to work very well, and recommend it.
http://itunes.apple.com/us/app/alchemy-synth-mobile/id432505977?mt=8