Clients

A tool and a library (usable from many languages) for client-side URL transfers, supporting FTP, FTPS, HTTP, HTTPS, TELNET, DICT, FILE and LDAP. (C) [GNU/Linux, Unix, Windows, VMS, RISC OS, OS/2]

Modular realtime chat client supporting IRC and SILC protocols. Supports multiple servers, themes, perl scripting and plugins. (C) [GNU/Linux, Windows]

Synchronizes a collection of mailboxes, which may be on the local filesystem or on an IMAP server. (C++) [OS Independent]

An embedable web server and client written in C++. It uses the OpenSSL library for all connectivity and is therefore based on solid ground as far as support for cryptography and connectivity is concerned.