Until recently, Linux PCs were about as easy to find in stores as a vinyl record. Now, personal computers with the Linux operating system pre-installed are becoming more readily available, thanks to new models from upstarts and established PC makers -- and disappointment with Microsoft's new Windows Vista OS.

In just the past several weeks, a handful of new, low-cost systems have hit the market that are powered by Linux -- open source software first developed by Linus Torvalds and enhanced by enthusiast programmers around the world.

Newcomer Everex, for instance, this month plans to introduce a robust Linux laptop.

Everex's Cloudbook runs a Linux distribution from gOS and includes a host of open source and free software tools, such as OpenOffice.org's desktop productivity suite, the Mozilla Firefox Web browser, and links to Google's gMail service.

The Cloudbook, which uses a 1.2-GHz Via C7 processor, is priced at $399 and is scheduled to hit shelves at Wal-Mart on Jan. 25.

Not to be outdone, Shuttle Computers last week at the Consumer Electronics Show unveiled its KPC Linux PC -- a $199 offering that runs Ubuntu Linux on an Intel Celeron chip and 512 Mbytes of included memory. Also at CES, MP3 player maker iRiver showed off Wing -- a handheld, touch-screen PC that uses embedded Linux.

Last month, Dell shipped a pair of systems loaded with the latest version of Linux available from Ubuntu. The Inspiron 530 N desktop and the 1420 N notebook feature Ubuntu 7.10 and a built-in software DVD player.

Demand for Linux systems is such that some retailers are selling out. Last year, for instance, Wal-Mart for a time couldn't fulfill orders for Everex's $199 gPC.

What's behind the growing interest in open source computing, long the preserve of self-styled computer geeks? Linux's increasing popularity among mainstream PC users may in part reflect a backlash against Microsoft. The company's new Windows Vista OS has failed to capture users' hearts and minds, let alone their wallets.

In 2007, only about 39% of new computers shipped with Vista on board, compared with the 67% of the new computer market captured by Windows XP in its first full year of availability in 2002, based on data from Microsoft and Gartner.

In spurning Vista, some PC buyers have cited concerns about its cost, resource requirements, and incompatibility with their existing applications. Indeed, the Home Premium version of Vista, not including a computer, costs more than Everex's gPC. It also requires 15 Gbytes of disk space and a hefty processor.

It's not just consumers that are seeking alternatives to Windows. Last week, the British Educational Communications and Technology Agency advised schools in the United Kingdom not to upgrade their PCs to Vista, suggesting they instead eye lower-cost Linux systems the next time they need new computers.

With a host of new Linux PCs hitting the market this year, U.K. schools -- and other buyers seeking computing alternatives -- will have more options than ever should they decide to steer away from Microsoft.