This week's "iPhone 5" rumors focus on the carriers. According to Piper Jaffray analyst Chris Larsen, via CNET, the "most noteworthy" change to Apple's next-generation iPhone is that it'll be offered by Sprint and T-Mobile, on top of existing carriers AT&T and Verizon.
In May, another analyst said an iPhone "4S" was launching on Sprint and T-Mobile in time for the Christmas holidays.
Meanwhile, ChipHazard reports that the next-generation iPhone is being field tested on AT&T's networks, according to a "well-placed sources in AT&T Mobility." The tests include signal reception and connectivity, and once they pass the tests the prototype will be given to manufacturers.
As for phone specs, there's an endless amount of speculation. Some of the more recent rumors include a completely revamped iPhone 5 with wireless juicing, a "baby iPhone" for developing markets.