Are you trying to run your own mail server, or do you need a mail client for linux?
If you don't have a didicated linux box on the internet 24/7 with a domain name, you may not want to run sendmail on your box. Sendmail is fairly complicated. From modifying the config file to setting MX records on the DNS servers, you really need to have a good understanding of how internet mail works before you can fully understand how to configure everything.
If you do want to run a mail server; have a dedicated linux box; static IP and domain name then this sounds like a good learning project. For starters, you should lookup all the HOW-TO documents on internet mail. There are several at
http://www.linuxdoc.org in the howto section. Then you can look at sendmail configuration specifically.
I like running my own mail server. It lets you receive any size email the other server is willing to send and it's great for fast mail downloads to my mail client, which happens to be MS Outlook Express. And with Apache running I can also run a web mail client, so I can view emails anywhere I have a browser.
Good Luck
Gary