As the Apple Worldwide Developers Conference (WWDC) approaches, we’re learning more and more about the next generation iPhone – including some things we already knew.

For example, the 960×640 display we’ve suspected for several months has been confirmed by the Czech website superiphone.cz, where you can see a cool video about how they checked the new display to confirm the leak.

In the video, Filip Kuzel from Mobilmania.cz, Tomas Holcik from Zive.cz and Vladislav Janecek from Superapple.cz put the next generation iPhone under the microscope. They found that it has four times as many pixels as the previous three generations. MacRumors notes that this increases the pixel density to 320 dpi (dots per inch), compared with Motorola’s Droid (265 dpi) and Google’s Nexus One (252 dpi).

With such a high pixel density, the new iPhones users will enjoy a much crisper graphic than any other smartphone currently on the market.