Ubuntu is one of the most popular versions of Linux
Fans of Linux hope that the move will persuade more mainstream PC users to abandon Microsoft Windows and opt for the open-source operating system.
London-based firm Canonical, the lead sponsor of the Ubuntu project, will ensure the software works on Dell PCs.
Ubuntu includes software like office programs, e-mail, a browser, instant messaging software and a media player.
Michael Dell, the founder, chairman and chief executive of Dell, is himself an Ubuntu user. He has the operating system installed on a high-end Dell Precision M90 laptop he uses at home.
'Strong endorsement'
For a long time Linux had been considered to be too difficult to use for normal computer users.
Michael Dell's home laptop runs Ubuntu
However, more recent versions of Linux distributions, like Ubuntu 7.04, have become much more user-friendly.
"Dell are going to work with us to make sure Ubuntu works fully on its hardware," said Chris Kenyon, Ubuntu's director of business development.
"For us it is a strong endorsement of Ubuntu and the unique support model we provide," he told the BBC.
Open-source software is developed by thousands of developers, and is usually free to use and download.
Firms like Canonical make money by providing software support for users of the operating system.
Dell has not yet confirmed which computers it will sell with Ubuntu pre-installed, only to say that it would offer Ubuntu 7.04 as an option on select consumer models in the United States in the coming weeks
Reports on internet bulletin boards suggest that Dell will offer Ubuntu on an e-series Dimension desktop, a high-performance XPS desktop, and an e-series Inspiron laptop.
Prices and availability in countries other than the US have not yet been released.
Benefits and drawbacks
Running Linux makes desktop computing cheaper, as it strips out the cost of buying a proprietary operating system from Microsoft or Apple.
Ubuntu promises users a complete software package
This has made Ubuntu - and other Linux distributions - popular not just in developing countries.
In France, the National Assembly has just started using Ubuntu on more than 1,100 desktop computers.
But using Linux also has drawbacks.
Most makers of software and hardware focus on Microsoft's Windows operating system, as it holds about 90% of the desktop PC market.
As a result Linux users often find that software - especially for computer games and accounting - does not work on their computers, and that plenty of hardware is not compatible either.
However, Mr Kenyon insists that Ubuntu is "an excellent option" for most users, especially if they want web, e-mail and standard office functionality.
He also points to the fact that Ubuntu is supported in more than 40 languages, with more to come.
And the more popular an operating system becomes, the more companies will start developing software for it, he predicts.
The man driving the Ubuntu project, Mark Shuttleworth, shot to global prominence as one of the world's first space tourists, when he flew to the International Space Station on board a Soyuz rocket.
The self-made millionaire from South Africa founded Canonical in 2004 to promote and support open source software projects.
OpenOffice running on Ubuntu 7.04.

Dell Inc. (Dell) announced Tuesday that, due to public demand, they will be offering an alternative to Microsoft Windows on a selection of their desktop and laptop computers. Dell will partner with Canonical Ltd. to pre-install the recently released Ubuntu 7.04 distribution of the Linux operating system.

Until recently, Linux distributions have not been adopted by mainstream computer makers due to concerns over ease-of-use. Newer distributions, such as Ubuntu 7.04, have become much more user-friendly, with features such as automatic updates and software installation.

Ubuntu director of business development Chris Kenyon told the ''BBC'' that one of the reasons Ubuntu was selected was its support features and hardware compatibility. "Dell are going to work with us to make sure Ubuntu works fully on its hardware," said Kenyon. A Dell representative suggested that the Ubuntu distribution was chosen due to public demand as expressed on a Dell-run forum website, ''IdeaStorm''. "It was overwhelming, the response we got to the survey," said Jeremy Bolen, a Dell spokesman. 

Tuesday's announcement was not the first for Dell's Linux offerings. They have offered servers and workstations with an optional enterprise version of Red Hat Linux for some time now. The chairman and CEO of Dell, Michael Dell, is reported to have Ubuntu installed on his own laptop. 

Perry Donham, an analyst with Aberdeen Group of Boston, suggested that the Dell-Ubuntu partnership will benefit Ubuntu more than it will Dell. "It's going to be a small part of Dell's market," said Donham. "But it's a great win for Ubuntu and for Linux in general."

Dell indicated that the Ubuntu-based computers would be available in the next few weeks, from Dell USA only for the time being. The pricing structure has not been revealed, or when such computers would be available in countries other than the United States.