Microsoft's new partnership with Novell may have some people wondering if Microsoft has given up on the server. Not likely, given their success with SQL Server, Exchange, and other back office products. This is further proven by their agreements with Zend on PHP, and earlier with XenSource.
Most enterprises are heterogeneous, with some servers running Unix or Linux, and some running Windows. Virtualization technology lets the same generic x86 hardware run multiple operating systems at the same time. This is the ultimate in flexibility for IT, but Microsoft could face a loss of potential revenue and mindshare if it's too easy for the control program, or hypervisor, to be free software. That's why they're so interested in building virtualization into the next version of Windows Server. All these deals are designed to strengthen that position.
The PHP move is just to catch Windows up in an area where they have been trailing. From a developer point of view, ASP.Net is associated with Windows servers, while PHP is associated with Unix or Linux. The agreement with Zend is simply a way to weaken the former association so that PHP programmers might at least consider deploying on Windows. Meanwhile Microsoft uses companies like Novell (Ximian) and Mainsoft to keep up the appearance of compatibility between .Net and Linux/Unix.
The strategy is really quite clever, and not without some advantages to the end users. Microsoft can use closed source tweaks to make a Windows-based hypervisor perform well with Windows guests, and they have the source code and relationships with Novell and XenSource to make their hypervisor perform well with Linux guests as well. Customers get more choice in that they aren't strong-armed into Microsoft-only configurations. Open source developers see their software get more validation in the enterprise.
If asked to name a loser in all the deal making of late, one might be tempted to say Red Hat. But open source companies are nothing if not nimble, so I wouldn't count them out just yet. Besides, some of the other big players such as MySQL, IBM, and Sun have yet to weigh in.