Assemble a group of rockers armed with the GarageBand and a compatible iOS device (all iPads, iPhone 4 and 4S, and the fourth-gen iPod Touch). Select someone to be the leader, tap the Jam Session note button in the upper right hand corner of the Track View menu, and select Create Session.

Make sure everyone is connected to the same Wi-Fi network or use Bluetooth to connect by turning on AirPlay in the Settings menu. Then have each additional band member tap the Jam Session button, select Join Session, and then tap the name of the Bandleader's iOS device to hop on board.

Once you've all joined the session, go to your instrument page. Make sure Bandleader Control is toggled on to keep things organized and toggle on Auto-Collect Recordings to make sure each mini-jam is saved to the Bandleader's iOS device.

The Bandleader sets the tempo, recording length, and other specifics of each session. When everyone is ready, hit record and start jamming out for the designated number of measures. The instruments will play through your iOS device's speaker, or you can plug in headphones to hear just your own.

When you're done, the Bandleader's iOS device will capture all the recordings from session.

Return to the Track View screen to play back and arrange the tracks your group has recorded. Here you can continue to fiddle with your tune, add instruments, and record additional parts to craft awesome songs with your GarageBand posse. Rock on!