How to enable POP in Gmail
and in the email program you want to use put this settings:
Incoming server: pop.gmail.com
Outgoing server: smtp.gmail.com
Use SSL whhenever there is a box to check and in SMTP settings if there are any, use password authentication, if there is one check the box for SSL and set the server port as 587.
You can use Gmail with Msn messenger but only to login and talk you wont be able to see your emails trough there.
To check for new messages without opening your browser use
GNotifier