In recent weeks I have banged on about Open Source, expending two articles on Firefox alone. Open Source applications make their code available to everyone. Disagreements and rabid balkanisation within the Open Source community aside, for our purposes the term might as well refer to free software whose licence allows you to share the source code, alter it, use it, do with it what you will.

The two great pillars of Open Source are the GNU project and Linux. I shan't burden you with too much detail, I'll just make the outrageous claim that your computer will be running some descendant of those two within the next five years and that your life will be better and happier as a result.

I am writing this article on a kind of mini John the Baptist, a system that prepares the way of the software saviour whose coming will deliver the 90% of world computer users who suffer under Windows from the expensive, clumsy, costly, ugly, pricey toils of Microsoft.

The Asus EEE PC perched on my knee combines GNU software with a Linux kernel powered by an Intel Celeron Mobile Processor to produce a very extraordinary little laptop. It weighs less than a kilogram, starts up from cold in about 12 seconds and shuts down in five. It has no internal hard disk and no CD drive. It offers 512MB of RAM, 4GB of storage and a seven-inch display; wireless, dial-out modem and ethernet adaptors are available for networking and internet connections, three USB ports, mini-jack sockets for headphones and microphone, a VGA out, an SD card slot and a built-in webcam. All for about £200 - less than the price of a show, dinner and taxi for two in London's West End.

When you press the EEE's power button, the lightning speed and quietness of boot-up tell you that you are in the hands of a solid state flash drive: no vulnerable moving parts and buzzing platters here. Within seconds a tabbed screen will appear on your display: the tabs are labelled Internet, Work, Learn, Play, Settings and Favourites. A click on each reveals a page containing bright, clear icons that relate to 40 separate applications and half a dozen or so selected web links. The applications include Skype, Firefox, Thunderbird (the Mozilla mail client) and OpenOffice.org, an Open Source suite of applications that allows you to create and edit Word, Excel and Powerpoint documents. One of the pre-installed web links is to Google Docs, which lets you do the same MS Office compatible work online. This combination of "server side" applications and Open Source software is, rightly, scaring the heck out of Microsoft which is in danger of relying, in a few years' time, on its excellent Xbox games console for income and kudos, its domination of personal computing a rapidly diminishing memory. Well, I'm allowed to dream.

The EEE is far from perfect: system software claims two-thirds of its meagre 4GB of storage, the keyboard is sub-par, the trackpad worse; it seems a shame to boast a built-in webcam and a full field of IM clients, yet be incapable of videochat; the OS, a customised version of Linux, part Debian, part Asus's own creation, makes downloading outside the bundled software updater uncertain. But these defects are minor compared with the machine's astounding value and functionality - and to the future trends in computing it heralds.

This is a computer designed as an introductory machine for children or adults, as well as a simple cheap do-it-all machine along the "One Laptop Per Child" model but which is also absolutely ideal as a truly cheap, portable, resilient device to slam into a backpack or briefcase. Everything you could want is there in free, Open Source form. It does not pretend to cater for the power user but, while file management is basic for the average person, tuxheads (Linux experts) can go straight to terminal mode and do their stuff. Meanwhile, for the rest of us, this is a wonderful little friend who does all we need straight out of the box. And it is only the beginning...

· Read Stephen Fry's blog here: stephenfry.com/blog/