Apple looks set to unveil a new iPhone later today at the Worldwide Developers Conference (WWDC) in San Francisco.

Mac blogger John Gruber, who has a track record of correctly predicting new Apple products, says he has heard that the phone's official codename is iPhone 3GS.

"I'm not certain that's what it'll be officially named, but my hunch is yes. I have no idea what the S stands for," Gruber said on his influential Daring Fireball blog, adding "1.Speed?" in a footnote.

Gruber's other predictions are in-line with various rumours currently circulating on websites, blogs and forums.

"I expect Apple to announce updated iPhones with significantly faster processors, twice the RAM, and twice the storage. I expected prices to remain the same as the current line-up."

Gruber also said he expects the battery life will be 15-20 percent longer than the current iPhone 3G. He also added that iPhone price cut stories are likely to be true.