Buried inside the Apple developer documentation is a brief rundown on some of the new features we can expect to see in June's iPhone 2.0 release. These same features are also available in the "Aspen Emulator" bundled with the iPhone SDK which also carries the OS version 1.2.

Bonjour
Full support for bonjour (Apple’s zero configuration networking scheme) will be included in iPhone OS 2.0. This allows you to discover and connect with other nearby iPhones. Bonjour is available in the foundation, core foundation and base system includes. This feature was existent but dormant in previous iPhone OS releases.

Full-screen mode in Safar
This means that Web apps can be displayed without the Safari address bar and other elements. With an appropriate meta tag, a Web app launched from the home screen can automatically be launchd in full-screen mode.

Support for SVG
(scalable vector graphics 1.1.): a resolution-independent image format that is highly compressible

A series of new CSS effects
Some of which are hardware accelerated, for transforms, transitions and animations

[via iPhone Atlas]