I think you just need to setup a POP account in Mail. You will need to know a few bits of information:
1. Your email address
2. Your user name (typically the part in front of the @ symbol)
3. Your password
4. The server that you get your mail from (usually "mail.yourdomain" where "yourdomain" is the part after the @ symbol)
5. The server that you will use to send mail (usually "smtp.yourdomain")
If you open the preferences in Mail (command-, ) and go to the Accounts area, you will see where to put the information. You may need to play with some of the settings to get it to work. You will also need to check with someone that is an administrator of the mail system to make sure that POP access is allowed.
Hope this gets you started!