According to a research note written to investors by Piper Jaffray analyst Gene Munster, the expected unveiling of the next-generation iPhone 4G by Apple at its June 7 Worldwide Developers Conference (WWDC), will likely see the launch of the handset exclusively on AT&T.

However, also noting that a Verizon version of the handset will probably be released later this year, Munster specified: “We believe that it is unlikely that the next generation iPhone will be available at Verizon (or Sprint) at launch; rather, it is more likely that it remains exclusively available at AT&T in the U. S. at launch.”

Munster has also predicted that the new iPhone 4G will become available for purchase by late June.

In fact, some unnamed sources from a few bigwig companies have also been confirming that Apple is testing an iPhone model with support for Verizon’s budding 4G network. This LTE-powered model will supposedly be released this summer.

In addition, some other reports also confirm that Apple has hired a Taiwanese company to ready an iPhone version supporting CDMA wireless networks, like Verizon and Sprint. The production of the CDMA model will commence in August or September.

Meanwhile, as per the already ‘leaked’ details, the forthcoming iPhone will run iPhone OS 4.0; and will feature Apple A4 processor; a 1 GHz chip; 512 MB of RAM; and a touchscreen with IPS and a resolution of 640 x 960.