How to do HTTP POST? Urgent! Please help!

Please help me how to do HTTP POST! Any hint, link, code is appreciated.

I created web form with a number of fields of different types ie. text, text area, number and date.

When user press Submit to send the information to a web service that will receive the information.

I have to use HTTPS POST to pass the parameters.

http://sservice.nnn.se/RegisterEntrie?user=[User name]&pass=[Password]& EntrieCode=ENTRIE-CODE&Title=Title+goes+here&Description=Description+goes+here

User should immediately get a confirmation that it has gone well or not.

Example output:

HTTP/1.1 400 Bad Request

[…]

Content-Type: application/xml; charset=utf-8

<?xml version="1.0" encoding="utf-8"?>

<ErrorResponse xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance

xmlns:xsd=“http://www.w3.org/2001/XMLSchema”>

400

Bad Request

field missing: Description