Engadget posted about some information they received from the ZiPhone folks. According to ZiPhone, they have spotted some code in the new iPhone 2.0 beta software that suggests Apple will use the Infineon 3G chipset. The code mentions "SGOLD3," which is a series of chips that Infineon produces. iPhone currently uses the S-GOLD2 EDGE chipset.
S-GOLD3H, also known as "PMB8878," supports 7.2Mbps HSDPA and has built-in acceleration and media playback features (which, incidentally, the iPhone already has and does well). This chip also includes a higher resolution camera, 5 mega-pixels instead of a 2. Engadget notes that the processor speed stays the same.