Whenever most people think of work software, they usually think of Microsoft's outstanding suite of programs collectively called Office: Word, Excel, PowerPoint, Outlook or Entourage and the numerous other bits and add-ons that come with them, depending on which exact version of Office you're using.

There are plenty of versions of Office and they all cost money, ranging from roughly £100 to over £300, which isn't exactly cheap.

Free from Windows

The clunkily named OpenOffice.org, though, is an extremely powerful alternative that seeks to liberate the world from MS Office in the same way that Linux has tried to rescue Windows users from their Microsoft shackles.

It includes a word processor (Writer), spreadsheet application (Calc), and presentation software (Impress) as well as a database manager (Base) and graphics creation package (Draw). And it's all free: you can download it at no charge.

The trouble with free, particularly when it does so many things, is that it can be a bit rough-and-ready compared to the more expensive commercial alternatives, even when they have big backers like Sun and Novell.

Mac native

For a long time, OpenOffice.org has had that rough-and-ready problem, particularly on the Mac.

In its earlier days, you had to compile it from source and patch it, making it inappropriate for virtually everyone but the most zealous and committed to getting things for free. Version two, available for Macs with PowerPC chips, required you to have the X11 windowing system installed, a relatively un-Mac-like world in itself.

Now version three – for Intel-equipped Macs only and not yet fully translated into British English from US English – takes OS X integration one step further.

For the first time, OpenOffice.org is a proper program that installs and runs like any other Mac app: download the disk image, mount it, drag the app to your Applications folder, double click it and you're there, using the familiar standard menus and keyboard shortcuts. It also ties into OS X's accessibility system, making it easier for people with disabilities to use.

Familiar interface

The integration has come about through a migration by OpenOffice.org to Java. This makes OpenOffice's OS X capabilities very similar but not identical to those of a native app.

All the same, to anyone who's ever used MS Office, OpenOffice.org is a very familiar experience. Many of the menu options are the same: most of the same functions are there; there's a new 'Start Center' just like Office's Project Gallery; even the wizards look similar and version 3.0 includes new icons that give toolbars even more of an Office feel, although they're nowhere near as polished.

Indeed, OpenOffice.org tries to be as familiar as possible, although where it does differ from Office, invariably it picks a far less intuitive, more complicated, usually more Unix-like way of doing things. The two packages aren't identical, but the learning curve for those making the switch isn't as steep as with some apps.

Open standards

But OpenOffice.org is also proud of, well, being open. Apart from being object-oriented, enabling you to embed presentations in word processing documents or vice versa, for example, by default OpenOffice.org saves files in the international Open Document Format (ODF), which is used by numerous applications and governments.

Version 3.0 includes support for the forthcoming 1.2 iteration of ODF. It can also import and save files in many formats, including the familiar Office DOC, XLS and PPT files, as well as, in version 3.0, the new Office 2007/08 DOCX, XLSX and PPTX formats.