Notwithstanding the fact it will be many years before very many corporate users might be able to work in a "Microsoft-free" environment, there appears to be significant effort being put forth to make it a reality. From the geekiest tech pubs, like the Java Developer's Journal to august ones such as The Wall Street Journal, circumventing Microsoft is a hot topic.
I choose "circumvention" deliberately, as many of the strategies intend not so much to eliminate Microsoft from the equation but to limit our dependence on Microsoft and limit the payments users make to same.
Some circumvention techniques are endorsed - and even sold - by Microsoft, whereas others are completely outside of its control.
In the former category, we find both "terminal services" and "virtual PC" technologies. Microsoft sells terminal services licenses directly and indirectly via its agreements with Citrix Systems. Virtual PC (and virtual server) technologies are sold in Microsoft boxes.
With terminal services, clients running on non-Windows operating systems - including Linux, Macintosh, Java and Solaris - can run native Windows applications remotely (and efficiently) using thin-client technology. While it doesn't eliminate Windows (and you have to be online to use it), it provides for client-side flexibility.
Where one needs to have full Windows available locally, virtual PC technology can be had from Microsoft or EMC's VMware division. With this approach, one can load and boot one or more Windows systems running "virtually" on "top" of a base operating system - usually Windows, Linux or Macintosh - that actually controls the hardware.
Again, while one ends up paying Microsoft for both the virtualization software and an operating system license, one gains the flexibility of using a different base operating system, thus circumventing Microsoft's stranglehold on your desktop.
The rise of the browser as the ubiquitous client portal has already loosened Microsoft's grip on the desktop. After all, if I use applications like Salesforce.com (and myriad others) that are built with the browser, I can get my job done from any browser-enabled computer - which is to say any computer.
Still, there are many sites built deliberately or inadvertently to Microsoft's Internet Explorer specifications. Sites that look fine viewed using Internet Explorer but downright bizarre when using, say, Firefox or Opera. (The Firefox people recently announced that they'd already reached 25 million downloads.)
While a user can (and many do) have multiple different browsers loaded, switching back and forth is a nuisance. According to an article in The Wall Street Journal in early March, Netscape 8 (in beta) contains both an Internet Explorer- and a Firefox-based rendering engine. Sites that it deems "safe" (the site owners are unlikely to exploit Internet Explorer's well-documented security flaws) are rendered using Internet Explorer or Internet Explorer components (no, I don't know the details). Questionable sites are rendered using the arguably more robust Firefox code (from which Netscape 8 was built). So, Microsoft is circumvented dynamically.
Much less visible but arguably more important is what is going on in the world of development.
Microsoft has devoted massive amounts of effort into making .Net into a top-notch development framework (and, I think succeeding in that effort.) Also, the Mono project was formed to allow developers of .Net applications to be able to run on non-Windows platforms (because Microsoft only provides a Windows run time). If Mono achieves its goals it will let developers leverage Microsoft efforts while ultimately circumventing Microsoft.
Finally, in the bowels of geekdom, you'll find the Apache Jakarta POI project, the goal of which is to circumvent (again) Microsoft by providing an API that lets Java programs access Microsoft Office file formats.
Check it out - this is the future.