A start-up teaming up with IBM to build "Microsoft-free" virtual desktops and deliver them through a cloud computing model has secured $4 million in first-round venture financing.

Virtual Bridges, founded in 2006, is part of IBM's attempt to undercut Microsoft's Windows 7 with a set of cloud - and Linux-based desktop packages. 

Virtual Bridges this week announced it received funding from Austin Ventures, reportedly in the amount of $4 million. The money will help expand sales, marketing and development.

The company just released the third version of its Verde (virtual enterprise remote desktop environment) software, which lets companies run both Windows and Linux desktop sessions. Although the software does work with Windows, Virtual Bridges is also part of IBM's Client for Smart Work initiative, which aims to provide a cheaper, Linux-based alternative to Windows 7.

The partnership combines Linux, Virtual Bridges' Verde software, plus IBM Lotus applications including Symphony, Sametime and Notes.

"By making these desktops 'virtual', a user can access the same desktop environment whether they are at home, the office, the road or anywhere where there is a machine connected to the network," Virtual Bridges says on its website.

Virtual Bridges lets the IT manager centrally manage workers' desktop PC software from a central server room.

The desktop virtualisation market is expected to grow significantly this year.

"We see tremendous potential for disruption and value creation in the burgeoning desktop Cloud and VDI market space," Austin Ventures investor Chris Pacitti said in the funding announcement. "Virtual Bridges has demonstrated innovative leadership in delivering not only best-of-breed VDI but also in combining VDI with managed desktops and disconnected use."