Yes there is.
Use IMAP and look at http://www.phpbuilder.com/columns/musone19990207.php3.
If you want to do it automatically, A crontab could be used to check the mailbox on a regular basis by calling the appropriate PHP routine.
I use this method for e-mailing data, as an attachment, to one of my websites. If the e-mail has the right sender and some recognizable features, it is automatically parsed and loaded into the database.
Rob