Some of the latest batch of converts come from the small and medium-sized businesses, a segment known for using Windows servers to run basic business, productivity and accounting applications.
"Linux is being used quite heavily by small and medium-sized business," said Scott Handy, director of Linux software solutions for IBM. "We've been partnering with independent software vendors who call on the SME market."
Through partnerships with independent software vendors, IBM has been able to convince customers that its Linux-based xSeries servers, along with supporting applications such as its DB2 database software, can make for a viable alternative to Windows.
One IBM software partner, Accpac International, a subsidiary of Computer Associates, made its accounting software available for Linux, and led to IBM winning a customer relationship with Westport Rivers Winery, a small wine maker based in Massachusetts.
"Our initial search was for an accounting package that ran off Linux," said Jamey Russell, IT manager and proprietor of family-owned Westport River Winery.
After some investigating, the company decided to go with Accpac's accounting software with DB2 on a server running Red Hat's Linux operating system. Additionally, Westport River Winery migrated its Windows 2000 servers used for print and file serving and Web access to a Linux server, and has switched to Domino, the messaging software from IBM subsidiary Lotus.
Russell calculated that the company would save between 3% and 5% on its IT budget over the next three years after the move to Linux.
"After that, our savings per year will be approximately 60% each year," Russell said, adding that, "Our goal is, within the next year and a half, to become a Microsoft-free office."
Westport River Winery said it plans to continue its migration to Linux in the next few months, when it will replace its Microsoft Office software with the open-source alternative OpenOffice.
The switch has been seen as a positive one for Russell, who said he has toyed around with Linux since 1995. And he said it has been equally as smooth for the 20 Westport River Winery employees who access the system.
"Right now we're really using Linux on the back end, which most people don't see," Russell said. "It's been very transparent for most people."
A second IBM Linux customer is New York record distribution company Satellite Records. The company of 100 employees is in the processes of moving its Web-based inventory management system to two Red Hat Linux servers from IBM.
"For small companies that don't have big bucks for IT infrastructures, if you get a Linux server set up it's probably going to work for as long as you keep it plugged in, and you're probably not going to have to do too much to keep it going," said Steve Shapero, Satellite's director of IT. "Our experience with Microsoft has been less than satisfactory."
The key to winning SMEs will be making sure that the applications they use to run their key business functions are available for Linux, said Stacey Quandt, an industry analyst covering Linux and open source software for Giga Information Group.
"I'd say the vast majority of people building applications for small- and medium-sized are doing it on our platform," said Peter Houston, senior director of Microsoft's Windows server product management group.
"We're putting $500m [£326m] into programmes to help generate business application development for the small and medium-sized business channel," he added.