April 14, 2009 
Douglas 
Apple has recently released firmware 3.0 Beta 3, build 7A280f, to developers. Along with the firmware there are also updates to the SDK. Changes include performance improvements, user interface updates and alterations to Spotlight search. How does this affect you? Well one big issues with Beta 3 is it will not run apps that aren’t made for 3.0. This means none of your apps would work but the ones you’ve developed for 3.0 yourself. (as of writing this article, beta 3 is not jailbroken either.)
UPDATE: The note below is for the emulator in the SDK, not for the firmware on the iPhone. (Thanks to Tetanus in the comments for this info)
“Applications targeting devices prior to iPhone OS 3.0 beta cannot be tested in this seed, this bug is intended to be fixed in a future seed.”
Arstechnica also notes there are updates to the API:
The major change in the UIKit API is that Apple has added separate types for the three notification methods: badge, text alert, and sound. Developers can register their apps for these different notification types individually for the needs of their users. Previously, apps registered to received remote notifications but controlled the type via settings. Developers we spoke to universally agreed that this was a welcome improvement.
Tags: 
Loading ...
So you aren’t (at the moment) able to run any app store apps?
all Apps work fine for me on the new update. Youtube finally works too.
Thanks for the update. If anyone else has any experience, let us know. btw, my YouTube has worked with each version of 3.0… weird. I’ve heard of others having the same issues though.
my youtube didnt work on beta 1 and 2
You are mistaken. Apps run just fine in Beta 3.
“This seed requires both the target SDK and testing device be set to iPhone OS 3.0 beta. Applications targeting iPhone OS releases prior to 3.0 beta cannot be tested in this seed.”
The above quote refers to testing applications in the iPhone simulator.
Thanks for the correction. Good to know!
In regards to you tube not working I was told before you install 3.0 you must erase you back ups from 2.xx. Also when you install a new version of 3.0 1,2,3. You must start your phone as new and not restore from back up. I had the same problem with you tube not working. I did a fresh install and did not restore from backup and my youtube started working again.
Can u send mms yet?
Yes mms ok
I installed and Jailbreak iPhone firmware 3.0 Beta 3 (7A280f) but for some reason whenever I’m installing from Icy, when I reboot the iPhone its stuck to the apple logo…any suggestions?