With the release of the iPhone 1.1.3 firmware update, Apple has given us the ability to create custom “webclip” icons (think “favicon” for your iPhone and iPod Touch) by adding a special file called “apple-touch-icon.png” to the root of your website (same place as the favicon). As an example, to the left is the new icon for SitePen.
If you have an iPhone, give it a whirl: hit the SitePen home page and add it to your home!
(Webclip icon linkage from Daring Fireball, Dan Dickinson, and Hicks Design.)