Internet Direct - The Indy Project

Indy is an open source client/server communications library that supports TCP/UDP/RAW sockets, as well as over 100 higher level protocols including SMTP, POP3, IMAP, NNTP, HTTP, FTP, and many more. Indy is written in Delphi Pascal and is available for Delphi, C++Builder, FreePascal, Delphi.NET, and Kylix.