Rumors are swirling that tomorrow Verizon will announce the availability of the iPhone to its customers. Currently, AT&T is the only mobile carrier in the US that offers the iPhone.

AT&T’s iPhone exclusive has been a financial blessing for AT&T, but for some consumers, it has been less-than-desirable, as AT&T has battled high-profile data outages that have left iPhone customers disconnected.

If the rumors that Verizon will be announcing the availability of the iPhone on its network on Tuesday are true, it may represent one of the biggest developments in the U.S. mobile market in years, and the potential implications could be far-ranging. Here are a number of the most important.

Carriers do battle

The major carriers in the U.S. are already battling over 4G, and a Verizon iPhone will certainly create a new front in the war between two of the largest carriers, Verizon and AT&T. Which carrier has the better network? Verizon thinks it does, and to back it up, it may, according to the Wall Street Journal, offer a plan with no restrictions on data use.

If the Wall Street Journal’s sources are correct, AT&T will have to hope that Verizon’s confidence in its network is missplaced.

Android faces stiffer competition

Competition between AT&T and Verizon won’t be the only thing that heats up if Verizon gets the iPhone. Competition between the iOS and Android will likely heat up as well.

Android has been on a tear lately, but in the U.S. market, one can argue that AT&T’s exclusive on the iPhone has given Android an advantage. After all, lacking the ability to offer their customers the iPhone, major carriers have pushed Android phones to their customers.

Verizon, of course, won’t ditch Android once it has the iPhone, but it will give its sizable customer base an attractive option that wasn’t previously available, which is why some analysts believe that the company could sell upwards of 9m iPhones this year alone. If that comes to pass, Android’s momentum going forward will be hard-fought.

Mobile ads and iAds get a boost

Millions of new iPhones could boost the mobile ad market, and Apple’s iAd network, in the most important ad market in the world.

As MediaPost’s Mark Walsh has noted, an army of new iPhone users “means millions more subscribers viewing or interacting with mobile ads via
Apple’s own iAd network and those of third-party mobile ad networks such as
AdMob, Millennial Media and Greystripe — both on the Web and within apps.

The iPhone app gold rush gets a second wind

What’s good for advertisers could also be good for app developers. The millions of Verizon iPhone customers will almost certainly purchase millions of apps, giving developers a new market to hawk their wares to.

AT&T loses, but it might also gain

While AT&T has seemingly benefitted from its iPhone exclusive, some have argued that the data usage encouraged by the iPhone has also contributed to its high-profile network woes.

If that’s the case, AT&T may ironically benefit as some customers ditch the company and bring their iPhones over to Verizon. Why? It may temporarily alleviate some of the pressures the iPhone has placed on AT&T’s network while it invests in improvements, and it will put Verizon’s network to the test.

Photo credit: bfishadow via Flickr.