A baritone is essentially a long-scale 6 string electric guitar. A standard guitar scale is in the 25" range. Most baritone models are in the 28" range. This gives them two more frets. This allows you to tune your guitar down a whole step. Making the tones deeper, but not as deep as a bass. The extended length allows you to use larger guage strings and tune the guitar lower without compensating action. Since you have to use the same string tension as a standard guitar. I'm not sure of a lot of famous guitarists that use them... but I know Mike Mushok from Staind uses one. I have been curious about getting a baritone axe as well... just for recording and experimental purposes. Like the last guy said though, you shouldn't have to learn anything new... it's just a guitar with a longer neck. You may have to adjust a little bit but as long as you have a good understanding of how to play, you should be alright. Just don't expect a baritone to be a shred machine... they're usually used for chugging rythym riffs or hard metal type of playing. Not fast solos and such.