Dr. Dobb’s has an interesting piece by Joel Eden on guidelines for designing touch=based systems.

Designing a good gesture or multi-touch based system is first and foremost about designing a good system that happens to be gesture or multi-touch based. Following a general overview of gesture, multi-touch, and multi-user systems, I explain in this article how you can leverage traditional UX designing for these new types of systems. Using four well-known user experience principles as a starting point — affordances, engagement, feedback, and not making people think — I explore how they can be applied to these new types of systems. Read more…