Interesting tidbit from the VIC Lotus Forms tutorial:

What Kind of Hardware Will IBM Techline Recommend?

It is important to note that all sizings are unique, but the product lines that IBM Techline will choose from when recommending hardware are as follows:

• xSeries – For Linux or Windows installations
• pSeries – For AIX installations

The xSeries scenarios can include a 2-way server, up to a 4-way server. The pSeries scenarios can include a System p5 510 or higher.

I had to chuckle because obviously IBM would want to recommend only IBM hardware.  Why not recommend zSeries for metaphysical scalability?    Anyway, the system specs state that Lotus Forms can run on Windows Server 2003.