Sometimes people would like to IRC from behind a firewall/proxy and are unable because the standard IRC ports are blocked. But usually web browsing is supported.
Any app can tunnel through a web proxy/firewall very easily with only a minor change to the code. All you have to do is open a socket to the proxy and write a "CONNECT <server> <port>" command to it. If it returns a 2xx code, you are set!
Here is a way to do it:
host= "irc.openprojects.net"
port=6667
proxyhost="companyproxy.com"
proxyport=80
if (proxyhost!=null){
Socket socket =new Socket (proxyhost, proxyport);
is = new DataInputStream(new BufferedInputStream(socket.getInputStream(),16384));
os = socket.getOutputStream();
PrintWriter out=new PrintWriter(os, true);
BufferedReader in=new BufferedReader(new InputStreamReader(is));
out.println("CONNECT " + host + ":" + port + " HTTP/1.0\n");
//do error checking here
String str=in.readLine();