report from the Wall Street Journal is indicating that not only will Verizon and AT&T be selling the iPhone 5 in mid-October, so will their rival carrier Sprint. The report indicates that Sprint will be selling the iPhone 4, most likely at a cheaper price point, as well as the newly designed iPhone 5.

Sprint Nextel Corp. will begin selling the iPhone 5 in mid-October, people familiar with the matter said, closing a huge hole in the No. 3 U.S. carrier’s lineup and giving Apple Inc. another channel for selling its popular phone.

Over the last few months, Sprint has lost major ground to its two major competing networks in the US. In the case of AT&T, much of that growth came from an exclusive agreement to carry the iPhone. Verizon began offering the iPhone earlier this year and has seen significant adoption rates despite the fact that the iPhone 4 was nearly a year old at the time. Verizon sold 4.5 million iPhones in the first half of 2011 and AT&T has sold 7.2 million this year.

Currently the iPhone 4 is available on Verizon and AT&T, Sprint’s two major competitors. The addition of Sprint to the ranks of the iPhone carriers in the US has long been considered a formality as Sprint’s CDMA network could easily support the iPhone designed for Verizon with just some small tweaks. Sprint has just over 52 million subscribers, while AT&T has 99 million and Verizon leads with 109 million. Shares of Sprint jumped 11% on just the headlines appearing on the WSJ site.

During its second quarter earnings call, Sprint blamed the iPhone specifically for a decline in its subscribers stating the fact that it was “the first full quarter both major competitors offered the iPhone.”

With both the newer, hotter iPhone 5 and the, presumably, lower-priced iPhone 4 on Sprint this October, consumers looking for choices outside of the big two carriers. The pull of the iPhone may be reduced because of its availability on all of the major carriers, but this is shaping up to be the biggest launch in the product’s history, so I wouldn’t discount the effect that it may have on Sprint’s subscriber base.

This is good news for Sprint, and good news for customers looking for more choice in plans and pricing. Sprint is currently the last of the big 3 carriers to offer a ‘true’ unlimited data plan. How long that plan would last after the network is inundated with typically data-hungry new iPhone users remains to be seen.