Yesterday Microsoft announced that their next Windows will be available for non-Intel processors also, i.e., the ARM architecture. ARM Holdings gapped up.

Nvidia ran up also, because Microsoft demonstrated a Windows version running on its Tegra processor line, which is based on the ARM architecture.

Even competing processor architecture licensor Mips Tech reacted, probably either because it is now seen as a takeover target or because Microsoft’s decision generally makes the way free for other processors than x86.

So, what does that mean now?
Foremost, this fine piece of news has to be seen psychologically. As soon as there are non-x86 Windows computers, even if they are pad or netbook-sized, there will be a market for other devices, e.g., powered by Linux on any more efficient processor and sized anywhere up to desktops or even to servers.
That is why Microsoft will probably not gain. The opposite is evenly likely. It is too late for them to catch up in the pad market, which is the direct idea behind this move and in their home turf, the desktop computer, this decision may ignite the Linux avalanche ;)
Sure, the iPad craze is still young, but for one, Apple and Google are formidable competitors. Secondly Microsoft’s operating system market share in these markets is zero. The old argument of MSFT being the late to the party coming crusher doesn’t hold here. For example, replacing Netscape’s browser with the Internet Explorer worked only, because they had the OS monopoly and Netscape was some orders of magnitude smaller.
Also, the biggest argument for Windows, the thousands of applications, doesn’t mean anything here. These programs need the current UI of Windows, mice and keyboards. Porting drivers is another time consuming hurdle. There is a long way to go for MSFT and their application providers to make a non-Intel Windows with a touch screen reality.
The direct winner, ARM Holdings, will probably see not so much revenue directly from computers with Microsoft, simply because MSFT will not get a significant market share in the pad computer market soon. Overall ARMH and MIPS and other smaller processor manufacturers should of course benefit.
Intel will be faced with even more competition from less power hungry and leaner processor lines. The old Wintel duopoly is beginning to sink.
Eventually the consumer could be the lucky winner. No more bloatware from Microsoft and Intel :)