Yes, it's possible; you'd use fetchmail to do this. You'd have to write a .fetchmailrc file and save it in the user's home directory, then log in as that user to start it when you boot the e-smith system. The file would go something like this:
set daemon 300 # Poll at 5-minute intervals
defaults
keep
# don't delete the messages after retrieving them
# I do this because I still want to use my normal client to get mail; I use the e-smith
# box as a webmail system.
# Use this for production
poll mail.earthlink.net protocol POP3:
user popusername
password thepoppassword;
# repeat as necessary