Having spent some time with lecturers talking about how they can use these tablets to help with their teaching, a number have asked about the availability of a stylus and whether you can use them to write on the tablet.
With the technology that is used for the multi-touch devices - capacative technology - a normal stylus doesn't work due to the requirement of electrical properties from the human body for the screen to know where you are touching. You can purchase a type of stylus that replicates this electrical property, but they are only as accurate as a finger with regard to writing.
The Engadget article states
Want to write on your tablet without all of the requisite finger grease? How about a stylus? Too pedestrian? What about a Smart Pen? Better yet, what about the aPen A5 Smart Pen? eFun's peripheral includes a stylus and a receiver that hooks into your iPad or iPhone's 30 pin connector, digitizing your handwriting or drawings via a number of compatible apps, including the company's own free Studio Basic Light. The A5 is set, broadly, for a release some time in 2012, and should run you around $99 whenever it actually hits the market.
This is a really interesting concept and may work well with our eFeedback & eAssessment iPad project.