Jakob Nielsen has done some usability testing on the iPad — the first person to publish results of any kind of formal user testing with the device, as far as I know. His results are interesting, but his conclusions are typically Nielsen-ish in their conservatism.
In short, he found that iPad apps are pretty confusing for [...]

I discovered something really handy today. A number of the icons that Apple uses in the iPhone UI are actually packaged as glyphs within the Apple Symbols font. Here’s how to get to them:

Open an application (works with most apps — I used TextEdit)
Go to Edit -> Special Characters
From the “View” dropdown [...]