Today iPhone 3.0 is available for download through iTunes.

The iPhone 3.0 OS (up from 2.2.1something) will include cut, copy & paste, landscape keyboard, a very necessary upgrade from SMS to MMS (get your pic messaging on), an improved calender and Internet tethering, among the necessary improvements included in the latest OS iteration

More on the new features:

Apple iPhone developers said the iPhone OS 3.0 software, which includes more than 1,000 new application programming interfaces (APIs), opens the door for new and innovative applications. A new push notification software capability, for example, is expected to lead new applications that provide audible or visual notifications to iPhone users.

And:

In order to deal with the fact that the iPhone doesn’t allow background processing, Apple has implemented a push-notification system that enables applications to gain the user’s attention even if the program is closed. For example, an instant messaging program will stay connected to an Apple server that can send notifications to the user if they get a message, even if the program is closed.The media functions have also been improved, as podcast playback has been improved, and Apple is bringing the “shake-to-shuffle” feature to the iPhone. Customers will also be able to access and buy movies, TV shows, audio books, and music videos over the air from iTunes, although these files aren’t allowed to exceed 10 MB if they’re downloaded over a cellular network.