Beta version iOS 4.1 became available on Apple's website tonight for developers

If you are a developer, you can try out the beta on your iDevices
The following phones and players are supported:
iPhone 4 (iPhone3,1_4.1_8B5080c_Restore.ipsw)
iPhone 3Gs (iPhone2,1_4.1_8B5080c_Restore.ipsw)
iPhone 3G (iPhone1,2_4.1_8B5080c_Restore.ipsw)
iPod Touch 2G (iPod2,1_4.1_8B5080c_Restore.ipsw)
iPod Touch 3G (iPod3,1_4.1_8B5080c_Restore.ipsw)
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From the innovations:- change of display of a signal of communication of the cellular operator
- Camera application now runs even faster.
- increased speed for iPhone 3G
- Added GameCenter for developers
- some cosmetic changes were made (we look at the antenna view):

(top iOS 4.0, bottom iOS 4.1 beta)
Xcode 3.2.4 and iOS SDK 4.1 beta (Snow Leopard) has also been released.

Everything can be downloaded from
me