Changing a Windows Network to Linux?

Charli125 asks: "I have been a Windows administrator ever since I got into the tech industry. I have no working experience with any other OS except for those from Apple. I am currently working with a small company that has 1 server and around 15 workstations. I would like to faze out all of the Windows software, in order to avoid having to deal with viruses, save money, and learn how the other half lives. Since I have never so much as installed Linux, I am looking for resources or advice on how to get started, and how to plan the change over. Can anyone help me?" "My current setup is like this:
Server-Windows Small Business Server 2003, Symantec Antivirus Corporate Edition(and for Exchange)

Workstations-Windows XP Pro, Office 2003 or XP, Symantec Antivirus, IE for most of the browsers (Firefox for mine and a few others). The main apps used are like every other office, Word and Excel.

I have OpenOffice installed on my home computer, and it works fine. I do see a problem with non-tech types saving in the default format though, which would result in other users not being able to read the documents/spreadsheets.

Yeah, I know, I'm so MSFT, I'm everything you guys hate about the IT world, but I would really appreciate anything that would help me get started.

Thanks"