Do you actually have Exchange running on the other networked machine? If not then you will just be using Outlook to check your POP3 internet mail, not to connect to an Exchange server. For those POP3 settings (POP3 server, SMTP server, username, password, etc.) check with your ISP or whoever is providing your mail service.
If you do have Exchange running on the other machine (which means the other machine is running NT 4.0 Server or Win2K Server) then you can find it's NetBIOS name by:
In NT 4:
1) Right-click on the Network Neighborhood icon and select Properties
2) Under the Identification Tab is a field called Computer Name
In Win 2K Server:
1) Right-click on the My Computer icon and select Properties
2) Click on the Network Identification Tab
3) Check the Full Computer Name field
Put this name into the box in Outlook and if everything is setup correctly you should be fine. Of course you will need to have added the proper user to the Exchange server in advance. Also if the computer name does not work you can use its IP address as Comtutor suggested. To find that on either machine:
1) Click on the Start Menu->Run and type CMD and press enter
2) At the Command Prompt, type IPCONFIG and press enter
3) Look for a listing in the resulting data labeled IP Address
Message back if you need futher help setting up the Internet Mail in Outlook. Good luck!