Although no specific dates for iPhone OS 4.0 availability were announced at today’s iPhone OS 4 event, Apple did provide general information on when the iPhone OS will become available for different users.
April 8, 2010: Apple releases iPhone OS 4 Beta (Developer Preview) to iPhone developers.
End of April 2010: Apple re-confirms that iPad 3G to be released, with iPad Wi-Fi released internationally; no additional dates are available.
Summer 2010: iPhone OS 4 to be released for iPhone 3G/3GS and second- and third-generation iPod touch, not prior-generation devices.
Fall 2010: iPhone OS 4 to be released for iPad. Possibly not version 4.0, but rather a follow-up.
Late 2010: Apple Social Gaming Network (“GameCenter”) to open.