Earlier today, iPhone OS 3.0 beta 2 was released to developers. The big news is that push notifications and in-app purchasing followed this release, giving developers a chance to try them out. Engadget has reported on significant instability with beta 1, so here's hoping that's been improved.
There's also good and bad news with this release. The good is that MMS and tethering are supported in beta 2. The bad news is that Apple asks developers not use them. It's like owning a Ferrari without wheels.
If you're a developer, you know how to get this. Let us know how it goes, and have fun.