Just to note that nginx has now support for Websockets on the release 1.3.13. Example of use:
location /websocket/ {
proxy_pass ​http://backend_host;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_read_timeout 86400;
}
You can also check the nginx changelog and the WebSocket proxying documentation.