The iPhone 4's (NASDAQ: AAPL) official roll-out date is June 24, but the folks at repair manual website ifixit.com got a hold of it a couple days early and took it apart. Some of their findings include:

• Steel belts surrounding the phone support it structurally and improve reception;
• The capacity of the 32 GB device is not as great as it looks, with just 28.77 GB available for the user;
• Battery life offers between 7 and 14 hours of talk time;
• 512 MB of RAM is available, which means a "smoother and faster" experience; and
• Antennas for UMTS, GSM, GPS, Wi-Fi and Bluetooth are integrated into the inner frame, which could improve reception.

Meanwhile around the blogosphere, critical reviews by early testers are largely positive:

David Pogue at The New York Times notes that even though the iPhone 4 comes with a better battery and faster processor, it is thinner and narrower than the earlier versions. The new operating system, iOS4, offers improved ease-of use, including mulit-tasking.

Walt Mossberg at The Wall Street Journal writes that when it comes to both software and hardware, the iPhone 4 is "a major leap" over the 3GS, but he notes continued concerns with the AT&T (NYSE: T) network, on which the device runs. In some tests, the latest version of the iPhone worked better than previous iterations, and in some cases worse, Mossberg writes.

Joshua Topolsky at Engadget writes that although the redesigned hardware makes room for a larger battery, it is not necessarily easy to replace the battery when you need to. Topolsky raves about the phone's new screen, which uses IPS and LED technology, making it possible to see the display in sunlight and low light alike.

For more:
- see the review at ifixit.com
- see David Pogue's post at The New York Times
- see Walt Mossberg's post at The Wall Street Journal
- see Joshua Topolsky's post at Engadget

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