How can you receive email from an alternate ISP?

I have two ISP Connections (one cable one dsl) both are imap/pop non SSL connections. How or what do I need to change in Outlook to be able to receive the email of the oppsite ISP's webmail. (Ex// Using TELUS, I want to DL messages from SHAW' webmail server.) I have all the inc/out going server info but no order or switch allows for me to dl'd the other w/ gettign a comunication error