Microsoft, which has been carving a larger slice of the mobile device OS market, is developing a new product, code-named "Crossbow," which will incorporate features such as instant messaging, a Microsoft executive confirmed Monday.Crossbow will have strong links with Office 2007 and Exchange 12, Microsoft\u2019s pending new office application suite and e-mail server, said Pieter Knook, senior vice president for the mobile devices and telecoms sector. Crossbow would be the successor to Windows Mobile 5.0, released in May 2005.Crossbow will take aim at the Symbian and BlackBerry operating systems. The OS will contain a new mobile version of Office Communicator, an Office 2007 enterprise communications application,\u00a0which includes instant messaging on public and private networks, Knook said."As the Office  PC versions of those applications improve, we\u2019re tracking that on the Windows Mobile side," Knook said.Knook said it\u2019s premature to say when Crossbow would be released, but the company plans for an annual mobile OS release. Mobile operating systems are also complex since operators often must be tested to ensure their systems can work with a new OS, a six- to 12-month delay after a release, Knook said.That process is nearly complete for the push e-mail capability of Windows Mobile 5.0, Microsoft\u2019s slow assault against BlackBerry e-mail that may now start to bear fruit. The company\u2019s new push e-mail capability depended on software upgrades on the telecom operators\u2019 side, as well as new versions of Exchange Server 2003 and Windows Mobile 5.0.Those upgrades are nearly complete, Knook said. "You\u2019re getting to the point right now where this quarter is really where the whole offer comes together," he said. Microsoft is hoping to nudge BlackBerry aside on costs and convenience for administrators. Knook estimates an enterprise deploying mobile e-mail with 20,000 users could save US$1.5 million in software purchases alone, plus additional costs on licensing over BlackBerry, he said.Microsoft is counting on strong connections with device manufacturers to strengthen its position with those enterprises already using Exchange but with a BlackBerry server. The new push e-mail feature would enable those companies to eliminate the BlackBerry middleware, which also consolidates their support structure, Knook said.-Jeremy Kirk, IDG News ServiceFor related news coverage, read Microsoft Exec: \u2018Huge Opportunities\u2019 in Mobile Search.This article is posted on our Microsoft Informer page. For more news on the Redmond, Wash.-based powerhouse, keep checking in.Also, have a listen to CIO Publisher Gary Beach\u2019s podcast on Microsoft\u2019s upcoming operating system, Vista, as well as the topic of open source.Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.