Astropad is the latest graphics sketching app for the ipad and it looks to be quite powerful.
Astropad transforms your iPad into a drawing tablet wired or wirelessly connected to your Mac with almost zero sync lag allowing for real time transfer. Also, integrated is customized Photoshop controls, including a floating pallette with Adobe-specific tools and iPad images are color corrected to match what’s shown on Mac. The app supports most styluses like the ones from Wacom.
With a $50 price tag, Astropad is pricier that most apps, but a bargain compared to dedicated sketch tablets. Click this link to head over to Astropad and watch the promo video below.