Capo.app
Capo is the ultimate app for learning a guitar solo. You drop in a song, and Capo can adjust the pitch and speed of the song for you to learn any song you’d like (well, any DRM free song). The functions themselves work suprisingly well; bending pitch and adjusting speed often distorts the song, but little distortion was found when I tried.
Capo is $40 introductory (this is a bit high for two features if you ask me), and will soon be $50.
Now, if you can rip out vocals, change the pitch and export, i’ll buy that.

One Comment
Capo is nice, too bad it’s so freaking expensive. I usually use Garage Band for all of this, but the added marker functionality is easily worth $20 bucks — but $50, c’mon give a poor guy a break. And the audio noise they introduce after the 5 minute trial is up is a real bitch move.
Great interface though!