"Billions and Billions Served" has long been a motto for McDonalds. Apparently, it won't be long before Apple will be able to make the same claim for the iPhone App Store. And, if Microsoft has a say, it won't be long before its upcoming on-device software marketplace will be hopping as well.

You see, the iTunes App Store recently celebrated its first anniversary. In that time, iPhone and iPod touch owners have downloaded an astounding 1.5 billion applications. 

What makes this number more amazing is that Apple originally didn't plan on allowing third parties to create software for the iPhone. At least that's what Steve Jobs and company asserted when it introduced the now ubiquitous smartphone in January 2007.

Today, there are over 100,000 members in Apple's iPhone Developer program and more than 65,000 applications on the App Store.

Every platform developer and their mother is attempting to emulate the Apple's success with their own on-device software store. Google's got one for its Android platform, as does RIM and Nokia for their BlackBerry smartphones, as well as Palm with its new webOS, which debuted on the Pre.

Of course, Microsoft's got an application store, Windows Marketplace for Mobile, up its sleeve for this for this fall. Redmond announced as much earlier this year.

Originally, it was thought the new on-device app store would only support smartphones running its yet-to-be released Windows Mobile 6.5 platform. Turns out that won't be the case.

This week, Microsoft announced the app store will be made available for Windows Mobile 6.1 and 6.0 devices as well. A smart move considering it will be a long time before Windows Mobile 6.5 supplants the earlier edition of the OS as the predominant version found on devices. Today, more than 30 million devices run on Windows Mobile 6.x.

According to Microsoft, it will start accepting submissions to the Windows Marketplace in 29 supported countries on July 27th, at which time it will also disclose the details of a Windows Marketplace for Mobile developer contest.

A key feature of the app store will be the Windows Marketplace Business Center. This category, according to Microsoft, "will contain mobile business applications across several common industries and line of business functions from leading companies... Business Center is another way for our partners to differentiate themselves and showcase their business applications, while making it easier for users to locate and purchase the latest mobile business tools."

All apps posted to Windows Marketplace for Mobile will be tested and certified. Developers will get 70 percent of revenue to Microsoft's 30 percent.