Another indicator that Apple is releasing a 3G iPhone in June appeared. In the latest iPhone 2.0 firmware an entry referring to Infineons SGOLD3H chipset has been found by jailbreaker ZiPhone.
SGOLD3H supports 3G and HSDPA. It is not ready for HSUPA, but as long as you are not streaming live video from your cell phone you will not need that anyway.
The iPhone uses currently the Infineon SGOLD2 chip.
More details on Apple Insider.
The 3G iPhone is expected to be released in June by many industry insiders.