Some third-party developers have been unhappy with Microsoft for complicating the ways they can port apps from Windows Mobile to the new Windows Phone 7 (WP7).

But not Fandango, the movie ticket site that built a WP7 app for Fandango from the ground up with two internal developers and outside contractors over a three-month period, said Darren Cross, head of business development at Fandango. He talked about the development process in an interview at the launch of nine WP7 phones here.

"We were lucky we didn't have a Windows Mobile 6.5 app," he said. "We built for WP7 [from] whole cloth."

Analysts such as Jack Gold at J. Gold Associates said that Microsoft will likely please Silverlight developers looking to build apps for WP7, but maybe not others who use different tools. The number of applications likely to be available when WP7 phones ship has been a mystery, but Microsoft has noted plenty of developer interest, with 500,000 copies of its toolkit downloaded.

Fandango used .Net and Silverlight development tools to make the WP7 application, and has already built similar apps for iPhone , BlackBerry and Android devices. Cross said it took about the same time and effort to build Fandango for Android as for WP7, although Android has proven more difficult because it has different device versions on the market and many device makers have their own interface overlays, such as the Touchwiz overlay on the Samsung Captivate.

BlackBerry has been the hardest to build for, given that it offers so many types of devices and different ways to input information. The iPhone has been the easiest, Cross said, because it is locked down in terms of its interface and hardware variations.

Fandango for WP7 offers much of the functionality found on other devices such as searching for recently released movies, finding movies nearby, and even buying tickets wirelessly. But Fandango navigation is somewhat different and involves swipes and gestures to access information, Cross said.

Fandango is now incorporating tweets on a given film, so would-be movie-goers can see what's being said and join in a social network experience about movies.

The fact that Microsoft has imnposed limits on hardware manufacturers by preventing them from introducing interface overlays helps developers like Fandango, Cross said. Otherwise, having to customize an app for the Captivate's Touchwiz overlay would have just added time to the development process.