How to retrieve popmail

[banderos]

I have followed the virtual mail system for postfix guide and have got it all up and running for my home domain
I now want to retrieve some external pop mail to my local maildir but not exactly sure how to set this up.
Can anyone give me some pointers as to what package I should be using?
cheers

[banderos]

I should say it doesn't matter if it's not to the same mailbox as long as I can access it via the same IMAP account