http://www.macrumors.com/iphone/2008/08/08/apple-releases-iphone-firmware-2-1-beta-3/

Apple has released Beta 3 of the iPhone 2.1 firmware. The new update consists of more bug fixes. iPhone 2.1 firmware offers some developers an early look at the next iPhone firmware with early support for background notificatoins.

Apple last seeded the second beta on July 30th.

hope this is released publicly soon

i'm sure it will be, since the current version is already cracked