Opera Software hasn't yet put the finishing touches on its forthcoming Mac and Linux browser releases. But the software maker plans to announce Thursday that it will make free versions of Opera 5.0 for both of these operating systems available later this year. Oslo, Norway-based Opera makes what the company claims is "the fastest browser on earth." It markets its compact, fast-loading browser as an alternative to the big two -- Microsoft's Internet Explorer and America Online/Netscape Communications' Navigator. Opera is designed to run on a variety of operating systems, including Windows, Linux, Macintosh, Be OS and the Epoc wireless system. The non-Java-enabled version of Opera 5.0 for Windows is 2MB in size; the Java-enabled version is 9.5MB. In early December, Opera began offering a free version of Opera 5.0 for Windows. The free version of Opera is supported by a single banner ad. Customers who are averse to ads have had the option of continuing to pay $39 per copy. Microsoft and AOL/Netscape offer their browsers for free. When Opera released the free Windows version, company executives said they planned to use customer feedback to determine whether to make available free versions of Opera for other operating systems. In the first month Opera made the free Windows version available, 2 million copies were downloaded, a company representative said. Opera has not yet tallied downloads for the second month. But two million downloads were enough to convince the company to make its next two Opera 5.0 releases available for free, said Pal Hvistendahl, Opera's communications manager. The Linux version of Opera 5.0 is in beta. The Mac version of Opera 5.0 is in internal alpha testing. A public Mac Opera beta--which will first be available for PowerPC-based Macs, followed by a version for older Macs--is expected shortly. A version designed for Mac OS X is also planned. Both the Linux and Mac versions of Opera 5.0 are slated to ship this year, according to Opera executives. Hvistendahl declined to be more specific on availability targets, saying that the next two versions will ship when they are ready. Opera is in the midst of striking deals with portal companies and other resellers to include Opera as part of their wares, Hvistendahl said. The Opera browser will be embedded in the Sony eVilla Web-surfing appliance, he said. And the company is close to finalizing a deal with a mid-sized portal company, which it expects to announce within the coming weeks, Hvistendahl said. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read what others have said.