John Gruber of Daring Fireball has stepped into the iPhone rumour arena for the second time this week. Initially Gruber gave some insight into the potential for background applications on the iPhone, this time the prominent blogger is talking hardware.

Gruber who has been accurate with rumours in the past concurs with speculation that the new iPhone will come in capacities of 16 and 32GB. On top of this Gruber also describes the new iPhone as having a 600MHz processor compared to the current 400MHz processor, but states that the “next-generation” CPU will give the illusion of being much faster than the megahertz increase would suggest.

Let’s say the rumors are right — and I believe they are — that the next-generation iPhone’s CPU will be running at 600 MHz. In the same way that, say, a 90 MHz Pentium was more than 1.5 times as fast as a 60 MHz 486, the 600 MHz CPU in the next iPhone will be more than 1.5 times as fast as the current 400 MHz iPhone CPU.

Alongside the change in processor the new iPhone will also sport 256MB of RAM twice that of the current iPhone.

As we’ve heard from other sources Gruber suggests that the external casing will remain very similar to the current iPhone.

Finally the Daring Fireball blogger confirms the presence of a digital compass (magnetometer) and the ability to record video. The new iPhone is said to have an auto-focus lens which will improve still photography and videos will be able to be edited and very easily uploaded to the Internet.

The new iPhone is expected to be announced at the WWDC 2009 opening keynote on June 8th.