MailLib is a free component for sending and receiving e-mails using SMTP/POP3.
The component can be used in Windows scripting, ASP or any other client application that supports COM

EAGetMail enables your C#, VB.NET, JScript.NET, ASP.NET or other .NET framework applications to parse and receive email based on POP3/IMAP4 protocol. Many advanced features are supported including TNEF parser (winmail.dat) and S/MIME. Easy-to-use and featured examples are included in the installation file.

Eclarsys PopGrabber is a simple program which retrieves Emails from POP3 accounts and forwards them to any SMTP Server
Completely free 3 account version available for download!
Works a a Windows service. Small .Net based program. Retrieving of your emails every minute possible!

Please note: Current version does not support SSL connections, SMTP authentication or catch-all mailboxes (each POP3 account is forwarded to a single SMTP account).

POP3 Pal is a portable mail client that lets you access your email from any computer. It has a built-in spam checker and supports multiple profiles, HTML formatted mail, attachments and templates. POP3 Pal is the perfect companion for people on the move. It's also a handy tool for mailbox maintenance.

No Spam Today! for Workstations was created for users of Outlook, Outlook Express and all other POP3 email clients to protect mailboxes against spam, malicious attachments and viruses. Acting between your mail client and your mail server No Spam Today! for Workstations scans all incoming emails and marks spam emails so you can sort out the unwanted emails.

POPcon connects MS Exchange Server(tm) to POP3 and IMAP mailboxes. It acts as an e-mail collector that retrieves messages from POP3/IMAP mailboxes and delivers them to your Microsoft Exchange Server mailboxes according to the intended user found in the mails.

All2POP is a gateway for POP3 client accessing various web-based email services e.g Hotmail, and Yahoo. All2POP takes care of your free, web-based email accounts, you no need regularly checking them; you are worry-free about losing your free, web-based email accounts.

MailBee POP3 is a powerful and easy to use COM object which enables ASP and Windows applications to receive, parse and delete mail from POP3 servers. Secure authentication, HTML mails, smart and fast MIME parser, email safety, and much more. Can be used in conjunction with SSL, SMTP and MessageCensor components. Royalty-free distribution.

Hethmon Inet.Mail Perseus is a complete SMTP/POP3 server for the Windows and OS/2 platforms. Perseus features remote administration on any Java enabled platform, unlimited mailing list support, auto-responders, custom filter hooks for specialized processing, local process delivery of incoming messages, multiple UCE system support, relay control, smtp after pop3 for roaming clients, extensive logging, and much more.

SMTP/POP3 Email Engine for Fortran
Email from your Fortran application. Simple API allows sending and receiving email, including HTML and MIME attachments. Knowledge of Winsock and TCP/IP is not needed. Includes multiple Fortran examples. Requires DEC, Digital, or ABSOFT Fortran.