I can see some options available:
1) Use PEAR\'s POP3 class --> tried it, having some weird weird issues like FF choking to death on their sample code!!!
2)
The native PHP IMAP functions support POP3 mailboxes, and will probably be faster than anything written purely in PHP. There are generally some useful comments and examples in the PHP manual, for example on the imap_open page.
I use the PHPClasses version. Works fine for me - I've been working on an AJAX mail client (personal project, learning exercise really). I also found that the sample code they provided was quite good so you should be able to get something working with it.
I've just discovered ezcomponents. Real nice to work with.