Developers of Moonlight, a Linux client version of Microsoft's new Silverlight multimedia technology, are closing in on feature-completeness, a leader of the project said on Monday.

A public alpha version of the open source Moonlight software is planned for September or October, said Miguel de Icaza, vice president for the developer platform at Novell and lead developer of Mono, a version of Microsoft's .Net Framework for Linux and Unix. Moonlight is dependent on Mono.

Tryouts of Moonlight will be offered to early adopters in a couple of weeks, said de Icaza.

Silverlight is Microsoft's cross-platform browser plug-in software for video and multimedia. Currently in a prerelease stage itself, Silverlight is expected to compete with Adobe's popular Flash Player.

Last week, Microsoft officials said a Linux client for Silverlight was a possibility but that Linux on the desktop paled in market share to Windows and Macintosh, where Silverlight is being supported by Microsoft. But de Icaza stressed the importance of having Linux clients support Silverlight as a means of accessing Web content. Linux needs to be a first-class citizen, de Icaza said.

Moonlight also is being extended to work on desktops outside of a browser, de Icaza said.

"It's a really powerful technology. In addition to supporting it on the Web, we're going to stick it on the desktop," de Icaza said.

Developers have had Moonlight running with Novell's Banshee media player and F-Spot photo management software. The desktop implementation of Moonlight is similar in functionality to Microsoft's client-based counterpart to Silverlight, Windows Presentation Foundation, said de Icaza.

At an event called a "hackathon," engineering groups have used Moonlight to improve existing applications, de Icaza said. They have been developing "desklets," which are small applications similar to Google Gadgets, leveraging Silverlight technology. De Icaza cited an appointment calendar as one example of a desklet.

"Needless to say, we believe that Silverlight is a fantastic development platform, and its .Net-based version is incredibly interesting, and as Linux/Unix users we wanted to both get access to content produced with it and to use Linux as our developer platform for Silverlight-powered Web sites," de Icaza said on his blog.

Word of plans for a Mono-based Silverlight Linux client arose around the time of Microsoft's formal introduction of Silverlight this spring. De Icaza said Monday morning he had just demonstrated Moonlight to some Microsoft representatives meeting with Novell.