Microsoft and Adobe are squaring up for the mother of all Web 2.0 battles with the release of competing internet applications. 

Microsoft has released the first developer preview versions of its Silverlight rich internet application development tool.

Rich internet applications are small, primarily multimedia applications that run through a web browser, such as web-based video players and slide-show programs.

Silverlight will compete with Adobe's Flash Player, which currently dominates the rich internet application market on the web.

Previously known as Windows Presentation Foundation/Everywhere, Silverlight has been in development since 2005.  

Silverlight will function as a browser plug-in for Mac and Windows. Microsoft's Internet Explorer, Mozilla's Firefox, and Apple's Safari are among the browsers supported by the Silverlight pre-release. 

A Microsoft spokesperson told vnunet.com that the first beta version of Silverlight intended for consumer use is scheduled for 30 April. 

Adobe issued a challenge of its own, announcing a streaming video player that the company hopes will compete with Windows Media Player.

Adobe Media Player will play Flash videos and includes such features as a ratings system and a favourites list for videos.

However, both companies will have trouble getting their respective products to stick, according to Van Baker, vice president of research at analyst firm Gartner. "It is an interesting dynamic to watch these two slugging it out," he said. 

Baker told vnunet.com that Adobe Flash and Windows Media Player have become entrenched in their respective markets, and that competing applications will have a very difficult time making any sort of a dent.

"It is going to be a very slow proposition to develop in the marketplace," he said. "You can put incentives on the table, but can they put enough on the table to cause a significant defection? Probably not."

Both companies made the announcements at the National Association of Broadcasters conference in Las Vegas.