There's more to .Net than just Microsoft's new XP brand name. Publicly, the Redmond, Washington, software giant is working overtime to pitch its new Windows XP operating system and Office XP desktop application suite as key components of its .Net software-as-a-service vision. But privately, Microsoft is pushing equally hard, if not harder, to sell developers on an upcoming set of Web services building blocks codenamed Hailstorm that could be used as part of a new offensive against America Online and its dominance in instant messaging. In short, Microsoft's strength is building software technologies and convincing developers to write applications and services for them. With Hailstorm, sources said Microsoft is attempting to position instant messaging as a complete development platform, rather than as a limited-purpose application. If Microsoft succeeds, instant messaging would expand beyond being a vehicle for simple chitchat to becoming the infrastructure for a range of Web services, including Web-based email, real-time stock quotations and calendar functions. "Microsoft is using Passport and MSN Messenger combined as the new key to fight [America Online]," said one software developer briefed by Microsoft on Hailstorm. "They are turning instant messenging into an architecture." Microsoft is preparing to show off the early fruits of its Hailstorm labors to a group of selected software developers and content providers 15 March. The company has scheduled a private, day-long design preview for its Hailstorm Web services technologies, said sources familiar with the plans. According to sources, Hailstorm would be a family of integrated software components, including new versions of Microsoft's Passport and its MSN Messenger instant messaging technology. Passport is an Internet authentication service that allows people to retain a single login that can be used to access Hotmail accounts, for example, from any device. Microsoft executives declined to comment on Hailstorm. Previously, Microsoft executives said the company will include versions of its current Passport and MSN Messenger service technologies in Windows XP home and business products. But Hailstorm will take those services further by integrating them with Microsoft's digital rights management technology, which is used to keep track of subscription-based Web content. Hailstorm also will include an industry standard security system, called Kerberos. "Hailstorm will give you user identity and location," the developer continued. "It can be hosted on any version of Windows, or even on Windows CE. (Hailstorm) will let your applications, like email, stock portfolio and other things, follow you wherever you log on." Hailstorm won't be the first .Net product shipped by Microsoft; it describes its Windows XP and Office XP products as part of its .Net vision. But beta testers have said they aren't sure which, if any, of the features in these successors to Windows 2000 and Office 2000 could be part of Microsoft's .Net initiative. Hailstorm also won't be the first set of programming components that Microsoft has made available to developers. With currently shipping versions of Windows, Microsoft delivers prewritten software building blocks, such as memory managers, graphical widgets and printer drivers, which they can use when writing Windows applications. Unlike these pieces of Windows plumbing, which were designed by Microsoft to help developers who are writing applications that run on a single machine, the Hailstorm technologies are aimed at developers writing new applications or Web services that can reside anywhere on the network and be accessed by any kind of device -- possibly even non-Windows ones, sources said. Take me to ZDNet Enterprise Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Microsoft forum. Let the editors know what you think in the Mailroom. And read what others have said.