I’ve seen all sorts of musical instruments running on the iPhone, but this is the first one I’ve come across that might involve getting a little spit on your screen.

Smule’s new iPhone app, Ocarina turns your iPhone into a fully-functional musical wind instrument. This amazing little application works very much like the real deal, combining touch, tilt, gestures and human breath to create ethereal sounds which bring out your inner Zelda.

Just place your fingers over four virtual “holes” on the multi-touch screen, and blow into your iPhone’s microphone. What’s really cool about the software is that none of the sounds are pre-generated, rather they’re built in real-time based on your exact gestures and movements.

Check out the performance videos below to see and hear Ocarina in action. First, a solo:

Now, a full orchestra of iPhone Ocarinas playing a little Led Zeppelin:

As you play, you can share your performances live with other Ocarina users across the globe (and let them rate your musicianship), thanks to Smule’s Sonic Network technology. Smule has even provided a nifty online score generator which makes it easy to play just about any tune you want.

Sound cool? What are you waiting for? You can get Ocarina today over at the iTunes App Store for just 99 cents.