WLM allows you to set up multiple email accounts.....I have Hotmail and my Orange email but could add others.these are both displayed on the front page and I get mail to both with just one click.
You should set up a new account in your Windows Live Mail using the exact settings you have for your other providers Email account...write down the settings before you start.
When you click on the new account button in WML there is a Wizard to help ...its not difficult...
http://windows.micros...-from-start-to-finish
Google something like the above for how to do it.
How this helps.