• Modules and Extensions
• Projects using Socket.IO
• Migrating 0.6.x to 0.7+
• Configuring Socket.IO
• Authorization and handshaking
• Socket.IO and firewalls
• Exposed events
• Using rooms

• How do I send a response to all clients except sender?
• How do I contribute to Socket.IO
• How do I serve the client?
• How does the Socket.IO protocol work

• Nginx and Socket.IO
• HAProxy and Socket.IO (with SSL)
• Varnish and Socket.IO
• Socket.IO Express and Sessions
• Compartilhando Sessions entre Socket.IO e Express (Brazilian Portuguese)
• Socket.IO Express and Sessions via session.socket.io (SessionSockets)
• Socket.IO on Clouds
• Authorization with Passport.js and Socket.IO
• Real time game with NodeJS and Socket.io
• Node.js para leigos - Explorando Real-time (Brazilian Portuguese)
• Real-time com Socket.IO no Node.js (Brazilian Portuguese)

Also checkout Socket.io on Hacker Notes

• nodecamp.eu 2011 (slides)
• nodeconf 2011 (slides)
• camp.nodejs 2010 (video)
• socket.io-pubnub 2012 (videos)
• dotJS 2012 (video)

• Erlang
  • yrashk/socket.io-erlang
  • yongboy/erlang-scoketio (Compatible with 0.9+)
• Android
  • koush/AndroidAsync
  • koush/android-websockets (Deprecated)
• Java
  • ibdknox/socket.io-netty
  • Ovea/Socket.IO-Java
  • Gottox/socket.io-java-client
  • yongboy/socketio-netty (Currently compatible with 0.9+)
  • c58/gnisio (GWT integration, Compatible with 0.9+)
  • keesun/mod-socket-io (Vert.x module, Compatible with 0.9+)
  • nkzawa/socket.io-client.java (Compatible with 1.0)
  • nkzawa/engine.io-client.java
  • mrniko/netty-socketio
• Lua
  • ignacio/LuaNode-Socket.IO
• Objective-C
  • pkyeck/socket.IO-objc
  • pashields/AZSocketIO
• C
  • yongboy/c_socket.io_server (Currently compatible with 0.9+, in development)
• C++
  • ebshimizu/socket.io-clientpp
• QT QML
  • misterion/qml-websocket
• Perl
  • vti/pocketio
• Go
  • davies/go-socket.io (Currently not compatible with 0.7+)
  • http://code.google.com/p/go-socketio/(in development)
• Python
  • MrJoes/tornadio2 (0.7+)
  • MrJoes/tornadio (0.6)
  • gevent-socketio
  • django-socketio
• Ruby
  • dkastner/Socket.io-ruby
  • markjeee/Socket.IO-rack
• Flash
  • simb/FlashSocket.IO
• Haxe
  • dionjwa/nodejs_externs
• PHP
  • Elephant.io
• .NET
  • SocketIO4Net.Client
• C++/Win32
  • Caloris
• unity3d
  • Unity3d.client