posting request - urgent

hello 

 i want to send up a request with headers which will give me a html file in
return.
could anyone please tell me hoe to make use of Libwww for this.  i want to
perform the foll. steps:
1. set up a connection with a server say srv , at  port say xx
2. post a request with parameter say getCAChain
3. add request headers with the foll. info:
Accept : text/*
UserAgent : myName
ContentType:application/x-www-form-urlencoded
4.send a request  : op=displayND&withCertChain=no&
navigatorFormat=no&submit=Submit

can anyone please tell me how to make use of Libwww for this...

thanx 
meenakshi