You didn't misread it. Yes ... Guitar Heros is making a leap to the portable realm with the upcoming release of
Guitar Hero: On Tour for the Nintendo DS. It will come with a special fret button grip attachment where you plug into the DS, and a special pick that you can use to strum the virtual strum bar on the touch screen.
You can see a promo video here:
http://dsmovies.ign.com/ds/video/article/8..._flvlowwide.flvAs you'll see, after attaching the fret button grip, you hold the DS sideways. You strum by slashing through the touch screen while the top screen (now on its side) displays the music pattern. They only showed two "right-handed" players. I'm guess they probably can have an option to flip it the other way for "left-handed" players.
Still, personally, I think it's gonna be hard on the hand that holds the DS because you'll be sort of twisting your wrist a bit and holding the DS one handed for a long period of time maybe a bit uncomfortable over time.