Microsoft (Quote, Company Info) Monday said it has teamed up with two U.S. partners to help it build a smartphone running its operating system for the first time in North America.

Building on its year-old wireless relationship with AT&T Wireless (Quote, Company Info), the Redmond, Wash.-based company says it has also teamed with Motorola (Quote, Company Info) to offer the MPx200. The clamshell style handset runs the Windows Mobile operating system and is based on the GSM (Global System for Mobile Communications)/ GPRS (General Packet Radio Service) standard. AT&T Wireless vendors will sell the devices primarily. Prices for the phones and service will depend on individual dealers.

"We are taking the next leap forward in unwiring the corporate office," AT&T Wireless Mobile Multimedia Services president Andre Dahan said in a statement. "The MPx200 is an ideal device for mobile professionals looking for a wireless extension of their workplace -- and for consumers looking for the ultimate in multimedia functionality."

Beyond mobile calls and basic organizer capabilities (phone book, calendar, tasks), the color screen phone also supports Web browsing via Pocket Internet Explorer and includes MSN Messenger service. Users can listen to Windows Media Audio (WMA) and MP3 music files and can add up to 1 gigabyte of expandable memory via memory disk.

Microsoft says customers can install applications and software on their handset wirelessly or from a PC via USB connection. The companies also say the MPx200 also will have "one-click" access to AT&T Wireless' mMode service (news, weather, sports, gaming) starting at $2.99 a month plus usage charges.

The device is expected to debut next month from Orange in Europe and from other distributors throughout Europe and Hong Kong. Motorola said the MPx200 should hit U.S. store shelves in the fourth quarter of this year -- just in time for the holiday season.

"We consider this alliance with Motorola to be a tremendous milestone for our Windows Mobile platform and a major win for customers, operators and developers," said Pieter Knook, corporate vice president of mobile and embedded devices at Microsoft.