WWDC opening event was finished by mentioning that apple releases XCode 3.0. I wonder if it will be available for tiger, or will only ship with Leopard’s seeds… This subject is still not mentioned on apple’s site…
probably it will be just leopard, and tiger will just get xcode 2.4

Xcode 3.0 is part of Leopard, and uses Leopard-specific features that prevent it from running on Tiger. Xcode 2.4 is the update of the development environment for Tiger.
Crhis: Xcode-3 has some leopard-specific features, but I am sure that some of the new ones would definitely work with tiger too. (I mean better syntax-hilighting, for example)