>I have done exactly what you discuss ... that is, setting up a Linux server on an existing Windows NT 4 network. I had a second server, you see, built using a 2u rack mounted cabinet and a Intel motherboard with integrated network, using Linux-Mandrake 8.2 as the server OS. It took me about a week to tune the thing, even though the install was able to parse the existing network and ascertain most of the configuration. Getting SAMBA set up actually took no time at all either, what took the week or so was when I played with it to change the sharing from public to certain users only, and authenticating those users against the NT PDC.
>
>It works, it works well, and because it uses Linux we didn't have to pay for an extra NT license or user pack or any of that mumbo jumbo. For all I know, it might even have taken me more time to tweak a new NT server ... so I consider the time taken to be essentially nil.
>
>Art
>http://members.aol.com/ARTGR

However, it seems that in "License 6" Microsoft is adding a 'tax' for computers at a company that don't have WinXX on them. So, if you have a network of 25,000 computers and half of them run WinXX and the rest Linux, the new MS license will require a fee for each of the Linux computers. THe stick is a threat of an audit if they don't comply with the new Licensing agreement, which locks them into two or more years of annual license upgrades. THis is really ticking people off.
http://k12os.org/

http://www.oregonlive.com/news/oregonian/steve_duin/index.ssf?/xml/story.ssf/html_standard.xsl?/base/news/10193037769515227.xml

The same strong arm tactics are being used on businesses too. It is exactly like a protection racket: "Buy the new license and you can avoid a lot of hurt (the BSD)".