using cgi form via http and extracting results

[bmgx]

I would like to use an already existing online service (currency 
converter) basically consisting of a html form with a few options that 
is submitted and returns the results. I really don't know where to start 
but I have assumed the following steps need to be taken:

1) Make an http connection to the remote script (http://server/script.cgi)

2) Fill out the html form (1x TEXT and 2x SELECT input fields)

3) Submit the form

4) extract the actual returned result. (using regex or something..)

Any help on which modules to use would be much appreciated!