The iPhone is still scheduled to ship this June, but some Apple consultants are advising customers not purchase the device until second-generation hardware arrives in late 2007 or early 2008.

A source at Macanics, a small IT consulting firm in Brooklyn, tells The VAR Guy that the iPhone’s initial performance could be limited by Cingular’s Edge network—which isn’t as fast as Verizon’s. “You’re at the mercy of Cingular’s data network speed,” the Apple advisor notes. Cingular plans to upgrade its service to a faster system, but support for that service won’t be built into the initial iPhones, according to the consultant. And the next generation of iPhones won’t likely arrive till late this year or early 2008.

So save your money, the consultant advises, at least until Christmas.