Apple last night released a new beta of its iPhone OS 3.0. The update which is only available to registered iPhone developers is beta 5 (build 7A312g) and delivers very few new changes.
The accompanying SDK which is build 9M2735 has one area of interest which is the inclusion of "StoreKit" classes which will allow developers to begin using in-app purchasing.
Apple also delivered a new beta of iTunes 8.2.