Today we got confirmation that Apple is in fact holding a big media event on October 4th to discuss the new iPhone. It had been rumored for a little over a week, and today an invitation was sent out that announced the time, date, location and simply said “Let’s talk iPhone.”

If the iPhone 5 is unveiled on October 4th, it has been theorized that the actual device will hit shelves sometime in mid-October. We know, of course, that AT&T and Verizon will have the device. But what about the guys in third place – Sprint?

Here’s why people think Sprint will be getting the iPhone 5 –

• Back in August, the Wall Street Journal reported that “people familiar with the matter” had pegged the iPhone 5 launch on Sprint for mid-October.
• A leaked internal memo from Sprint higher-ups advised Sprint employees to provide a “no comment” to any customer who asked them about the upcoming device.
• Earlier this month, rumors emerged that Sprint was busy installing network repeaters in Apple Stores to boost signal strength, apparently in preparation for an iPhone launch.
• Then, another leaked memo suggested that Sprint was blacking-out the first two weeks of October for the “possibility of a major phone launch.”

Of course, there has been no direct confirmation from Sprint regarding the next-gen iPhone, but many speculate that the network will offer the device when it finally launches. And when they do, it might come with an unlimited data plan.

At GigaOm’s mobilize conference, Sprint’s CTO Stephen Bye said that Sprint was committed to unlimited data plans.

From CNET –

“There’s clearly a cost to support unlimited,” Bye admitted, adding that not every unlimited subscriber is as high a data user as his or her neighbor. At the same time, Bye emphasized the simplicity of supporting an unlimited data plan, citing the hidden cost for customer care and support related to tiered data plans

Bye acknowledged the pressure of sticking with an unlimited data plan, however. “There’s a challenge for all engineers to work on how we get the cost structure down,” he said.

If it actually comes to pass, having the new iPhone on its network could strain Sprint’s attempts to keep the unlimited data option for customers. But for now, they say they are committed to keeping it that way.

Earlier this month, inside sources quoted by Bloomberg said that there was most definitely going to be an iPhone coming to Sprint. They also said that it would, in fact, come with an unlimited data plan.