It appears Apple’s iPhone uses the following User Agent:
Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543a Safari/419.3
A quick search of the log files turns up a hit for me. IP address is from Apple, so I’d presume it was using WiFi to connect via Apple’s corporate network, and not Cingular’s Edge network.
I’m curious what version of WebKit will ship on the final product. This could possibly be it.
[Hat tip: Mac Rumors]