It may be hard to believe, but the the long-awaited white iPhone 4 is now available through Apple’s online and retail stores. Apple made the official announcement early this morning in an email and the company’s website now lists the pale iPhone 4 as available for both Verizon and AT&T.  The phone is also expected to be available through select retails as well as through AT&T and Verizon stores.

Apple stores in the U.S. are just beginning to open up, but reports out of China have indicated that hundreds of people were lining up and waiting for hours in hopes of being able to purchase the device. The white iPhone 4 goes on sale today in more than 20 countries.

For a time, the white iPhone’s release seemed unlikely to ever happen. Originally spotted in Steve Jobs’ own hands, the phone suffered repeated delays following the release of the black iPhone 4 last summer. Just as the tech world was ready to give up on the device, rumors began swirling that Apple would follow through with a release during the spring of 2011. Those rumors have now proven to be true.

So why the long delay? It turns out that that the white iPhone 4 is just as susceptible to UV rays as human skin is. Apple needed the time to make sure that the phone’s internal components were adequately protected from the sun’s effects before it was ready to launch.

“It was challenging,” Apple senior vice president Phil Schiller said in an interview with All Things Digital. “It’s not as simple as making something white. There’s a lot more that goes into both the material science of it–how it holds up over time…but also in how it all works with the sensors.”

If you’re all set to buy your very own white iPhone 4, note that it may take awhile for it to reach you. Apple’s website currently says that the black iPhone 4 is shipping in 24 hours, but the white model within “3-5 business days.”