Outlook with Local Area Network

My office has connected to the Server using LAN. Currently we do not have internel email.We also used SQL server 7 as our database and using Office 2000 Pro for daily operations.Since all computer were connected, can i use Ms Outlook as an internal email?
If so what are the best way to configure it.
Can we shared the post office for those email profile? Do we need to installed Ms Exchange to the Server?.Can somebody guide me on these issues?