Here is a tool I had to pay 99 bucks for but I didn't mind because when I sit down and play the guitar and come up with some cool licks or even a full classical piece it makes a midi copy note for note. I exchanged a lot of emails with the developer when it was in Beta and he is a really cool guy. AND, obviously once you record a guitar lick you can play it back in real-time or later as another instrument.
In other words, if I am channeling the output to Aria, I can use the electric guitar to play violin--or anything else.