Exchange 5.5 and POP3

I need some advice…Exchange server is inside firewall, using mail relay server on DMZ for SMTP traffic. I need to allow users in remote office (2) access to download POP3 messages, but I don’t want to open POP3 on the firewall and I don’t want touse OWA. Is there a POP3 Relay product out there that I can put on the DMZ…