central authentication,outlook hosting at central system

[psreddynl]

I am new to network administration/client-server administration and setup.I am hardware engineer and i know peer-peer networking only.I am working at a startup company.i need help for following questions.

we are having ten systems in three different rooms.Already LAN IS THERE.

1. How to make outlook application centralising at one computer and anyone can download or access mails from any system in network ie LAN.(without static IP expecting the idea)

2. How to make authentication from a centralised system ie i mean how to make a system as a server and remaining desktops as clients.os will be at local clients and all authorization will be from central system, applications should be installed on central system only.

Thanking you in advance