This is a list of the bugs discovered by the iPhoneWebDev list members. If you have any more, or if you have workarounds or examples for those here, please let us know and we'll add them.

RADAR PID Description
5306037 Bug in dial strings, probably in 'tel:' scheme.
Phone numbers sync'ed to the iPhone with 'w' and 'p' values are not dialable.
5306129 window.onresize does not work
5313789 Input keyboard is bugged in chat-style apps.
Demonstrates issue: http://enrogue.com/lace-broken/
Fixes issue: http://enrogue.com/lace/
5313966 window.pageYOffset always returns 0.
Demonstrates issue: http://enrogue.com/iphone/
(???) mousedown event does not trigger on "fingerdown", it triggers along with mouseup on "fingerup".
(???) Bare images on default viewport.
Bare images (e.g. http://my.company.com/image.png) are rendered on the default 980px viewport, rather than being sized to fit the screen, which forces people to embed images on pages to get them to work right.
(???) Re-showing URL bar impossible.
It's possible to hide the URL bar (window.scrollTo(0, 1)) but it seems impossible to show it again. Bug or feature?
(???) Back button and hashed locations.
Sometimes when you hit the back button, it doesn't go back to the previous hash, it goes to the previous url.
5325294 Fixed positioning bug.
Fixed positioning does not allow users to position e.g. "toolbars" on the iPhone. More information.