People are having issues with connecting to the Apple servers at the moment, Siri might not respond. I'm looking into it.
WARNING: The Preferences.app in the Applications folder included with the download should NOT be used for now. We are working on a solution to fix the Preferences.app! If you do replace the Preferences.app, you might end up with a non working Settings app, so please take this warning serious!
iPhone 4 GSM
iPhone 3GS (experimental)
iPod Touch 4G
iPad 1 (needs some tweaking)
iPhone 4 CDMA
+ All devices that are not able to run iOS 5
Untested devices (please test and tell me!)
iPod Touch 3G