Here' s what Frontier Design has to say in their own words...
iShred LIVE sends your guitar sound through a bank of crazily configurable stomp box effects, rendering the result into screaming, distorted, wailing, looping, feedback-fueled audible gold! Never before have you had so many awesome effects for your guitar ... in your pocket!
Pick up iShred LIVE for FREE in the iPhone App Store and get started today with the built-in Amp Sim and three default effects: Buzz Kill noise filter, HK-2000 delay, and Q-36 flanger. Additional effects can be added through the built-in store for only a buck or two. iShred LIVE includes a built in chromatic tuner, metronome, 48 preset slots to store sounds, and a music/loop player to help learn and perfect your art. iShred LIVE supports up to four effects and the amp sim at a time. Nothing else comes close to being this easy or sounding this good!
To get things started you'll want to hook your guitar to your iPhone (or iPod touch/iPad). Frontier Design Group has teamed up with Griffin Technology and recommends their Guitar Connect cable, a specially designed interface cable that makes it drop dead simple (and inexpensive!) to get playing right away.