An interesting application for the DS.
Basically you use the bottom screen to strum and you press the shoulder and face buttons to pick chords. You do have the option to customize your own chord palletes to pick whichever ones you like the best and you do have the option of adding effects such as distortion and flanger to your simulated guitar. For what it's worth Jam Sessions does a good job at what it's mean't to do and does sound like a guitar but being unable to play individual notes means lack of shredding for some players.
It's a good app but not something you can really spend hours playing.