Amidio (http://amidio.com/) has released Star Guitar, an US$3.99
iPhone/iPod touch application that enables the user to play automatic
guitar rhythms, both strumming and picking types. It’s based upon
patented one-screen interface “StarChords,” which allows immediate
selection of 144 chords.

Those chords can be strummed in a manual way (thanks to the
“SmartStrumming” technology), or automatically. All sounds are
generated in realtime with the new “SampleMagic” technology.

Almost any song can be played on Star Guitar with just 10-20 screen
taps, according to the folks at Amidio. There are 22 different guitar
rhythm patterns (pop, reggae, jazz, ballad) in Star Guitar 1.0 and
the library is extendable. There are three guitars by default:
Acoustic Silver, Mellow Jazz, and Electro Chorused.

Users can also use voice recorder and record guitar and voice
simultaneously. Among the features are: .WAV export; a built-in Wi-Fi
server; direct export to Intua Beatmaker; overdub recording; loading
custom loops for playing in the background; and built-in help.