Most of Adobe Systems' products remain proprietary; the company's Photoshop graphic editing application sells for $649.99 on Best Buy's Web site. But that doesn't mean Adobe can't make nice with the world of open source.

The company announced plans Monday to join the Linux Foundation and released an early test version of its Adobe Integrated Runtime (Air) for rich Internet applications.

"Adobe's decision to join the Linux Foundation is a natural extension of its commitment to open standards and open source, which demonstrates its leadership and foresight in the software industry," Jim Zemlin, executive director at the Linux Foundation, said in a statement. The Linux Foundation sponsors the continued development of the Linux kernel by Linux creator Linus Torvalds and advocates on behalf of Linux and open source in general.

Adobe CTO Kevin Lynch has expressed an interest in increasing its contributions to open source and standards. Among those products Adobe has open sourced are a software development kit for the Flex development framework and BlazeDS, which helps serve up data-intensive rich Internet apps, as well as an open source implementation of ECMAScript called Tamarin that includes the scripting engine of Flash Player. The company has joined the SQLite Consortium and participates in open source conferences.

Adobe's also developing software to run on Linux, now including a Linux version of Air, which Adobe had earlier promised. The version Adobe made available on Monday is just a pre-release alpha version, with the final version expected later this year. Along with Air, Adobe also released the latest update to the alpha version of Adobe Flex Builder 3 for Linux.

That said, and though Zemlin applauds Adobe's commitment to open standards and open source, it may take a while for open source to filter throughout all of Adobe. Only a few of the company's products have been open sourced and the company's biggest cash makers still cost gobs of money to buy. Meanwhile, the company's most ubiquitous product, Flash Player, uses the proprietary ActionScript extension of the ECMAScript standard and Adobe has been pushing its own PDF format through standards bodies.