Some notes from the WWDC iPhone development session have leaked today (and abruptly taken down), but have yielded the following extremely useful bits of development info.

Flash and Java will not be supported by Safari at launch

The device width reads as 480px, not the 320 that most developers have been assuming.

Media = “mobile” will be supported in the CSS spec

HTML5 is supported

Javascript is limited to 5 seconds’ runtime before (we assume) the process is killed in order to keep the iPhone responsive.

Quicktime will be used, and the optimized setting for video on the iPhone is H.264 baseline profile 3.0 up to 640×480.

Assuming that several of these keypoints are true (notably the 5 second Javascript, Flash and 480px), many developers who have gotten a headstart into writing apps may have to rethink things a bit.We’ll be updating our own development guide page with this information once it has been confirmed.