What speed does the A4 in the iPhone 4 run at?

According to MacRumors and some German source the iPhone 4 is somewhat slower than the iPad, but still significantly faster than the iPhone 3GS. I guess that its A4 CPU is clocked at about 750 - 850 MHz.

The iPhone 4 is based on the same processor that is seen in the iPad and has a clock speed of 1Ghz.

The iPhone 4 also has 512mb of RAM which is double that of the 3GS and although never officially announced also double that of the iPad.

Though it's not confirmed, most sources claim that the A4 in the iPhone 4 is the same processor that runs the iPad, clocking in at 1ghz as you suggested.