The Wall Street Journal recently reported that the iPhone 5's release will be in mid-October on Sprint's network, giving the third-largest carrier in the U.S. access to (by many objective and subjective metrics) the hottest smartphone on the market.

They might not be the only ones adding the iPhone to their phone lineup. T-Mobile USA could also be getting the iPhone 5 some time in early to mid-October, reported CNET, citing blog MacTrast. 

A source told the blog that iPhone 5 would operate at 3G speeds on T-Mobile's network. If the source's claim pans out, the phone would be released simultaneously on all four major U.S. carriers as an unlocked phone capable of use on any network, MacTrast wrote.

Apple has been dominating the U.S. and global smartphone market, capturing 19.7 percent of market share by shipping 20.3 million units in second quarter 2011. This despite the fact that its flagship iPhone 4 is well over a year old, which is ancient in the technology world.

The highly anticipated release of the iPhone 5 is expected to be wildly popular with consumers and possibly extend Apple's lead in the smartphone market.

If Verizon and AT&T continued to have it for themselves, they would have a meaningful advantage in acquiring U.S. customers.

However, if the four largest U.S. carriers will all have the iPhone 5, the biggest winner will be Apple itself because its phone will have access to more distribution channels in the U.S. than it ever had before.

The iPhone 5 is expected to sport a faster processor, a wider screen, and the iOS 5 operating system.