Since first writing this document I have gained a great deal more experience with Linux and some of the tools mentioned here. I now use Linux in a wide variaety of tasks at home and work. I have since moved from the company for which I set this particular server but to my knowledge they were still using it some three years later ( I think they replaced it with a newer Linux based sollution arouind this time). If you are considering using Linux as an alternative to another OS I would encourage you to look into it.
Not only have I moved on but the changing face of Linux has meant the necessity for this document has decreased somewhat. Many distributions (try looking here http://www.linux.org/dist/ ) have made using Linux as a Windows-LAN server even easier by pre-configuring the options needed. Often you can find a dedicated product specifcally for the purposes mentioned here.
However there will always be those who want to "get their hands dirty" or just want to do things for themselves and learn through that process. I can sympathise with this as the experiences shown here served to teach me far more about Linux than I first anticipated.
Also, as the world of Microsoft moves away from clients such as Windows9x, there has arisen a need for provision of things like shared calendars, address books etc. ( basically replacing Microsoft's Exhange Server ). Much of this functionailty are available under Linux through various applications and tools, some proprietary, but I decided against listing them here as I felt it best (and simpler) to keep this document within it's original purpose. If you require these things, have alook at some of the products available through various distributions which aim to provide all of the functionality listed in the document in one go.