Smule, makers of the iPhone’s Ocarina, have followed up their hit application with Leaf Trombone World Stage, a rhythmic app billed as “The Massively Multiplayer Musical Game.”

As the name implies, Leaf Trombone effectively turns an iPhone into the brass instrument. Players either blow into the iPhone mic, or simply touch the screen via the app’s touch mode, while moving a slider back and forth to make music. Reference pegs guide beginners to the proper notes, making for a simple and effective music experience. An automatic accompaniment is included to enhance the piece.

Smule also harnesses the user community by allowing players to upload pieces and judge performances, rewarding achievements for those gaining high marks.

Smule’s last hit app, Ocarina, is currently listed in App Store’s All-Time Paid Apps and has garnered much praise from the iPhone community.

Both Leaf Trombone and Ocarina are on currently on sale in App Store for $.99.