Apple is going to announce the iPhone 6 tomorrow on Sept. 9, and many are speculating that the smartphone could be available for purchase as early as Sept. 19, just 10 days after Tuesdays announcement. The iPhone 6 will supposedly come in two different sizes, a 4.7-inch version and a 5.5-inch version.

These phones will probably retail off-contract for anywhere from $600-$1,000. Yikes. That's why most people opt for a 2-year contract or contract extension when buying an iPhone, that way the majority of the phone's cost is subsidized. The only thing that sucks about two-year deals like that, is you can't upgrade your phone for two years. 

And with the iPhone 6 looking like it's going to make even the sleek iPhone 5S look like a piece of drab design, if you're an Apple fan, you're probably going to want to upgrade this fall if you can. We've put together an eligibility guide for the major four US mobile carriers to help you find out if you qualify for an iPhone 6 upgrade. Find your carrier below for instructions on how to check your eligibility.

Verizon

Verizon users just need to dial #874 on their iPhones to find out when that phone is eligible for an upgrade. Once dial #874, you should get a text message back informing you of when you are eligible to upgrade your phone. Users can also check by logging into their account on Verizon's website.

AT&T

AT&T will tell you when you're phone is eligible for an upgrade if you call *639#. Once you dial that, you should get a text message back informing you if you're eligible for an upgrade at that time. You can also check eligibility by logging into your AT&T account on their site.

Sprint

To check upgrade eligibility on Sprint, text "upgrade" to the number 1311. You should get a text back informing you of your eligibility status. You can also find out your eligibility status by logging into Sprint's website.

T-Mobile

In order to upgrade on T-Mobile, you have to be part of its Jump program. The Jump plan requires you to pay $10 extra a month for the ability to upgrade your phone whenever you want. If you're on T-Mobile and  you're not part of the Jump program, you might want to take a look at it.

Stay tuned to our site for our ongoing iPhone 6 and Apple coverage as we bring you all the details about the latest Apple hardware launching this fall.