Well not striclty true - LCDC doesn't check to see if the mail has got to your outlook/express inbox, it actually polls the POP3 mailbox on your download server to tell you when you have mail waiting to download.
yes yes yes... it checks the POP directly so you don't need to have the mail program running (kinda nice)... I just finished my rig and did just that. Got a blue LED connected to the GPO flashing on upcoming mail as well as the LCD switching to mail display and telling me which mail box as new messages... kinda cool!