You might also wish to take a look at WWW::Mechanize. Some tools that can assist you in creating scripts for WWW::Mechanize (which has its own cookbook) include HTTP::Recorder and Ethereal (the latter being a Network Protocol Analyzer which lets you see exactly what your browser is communicating to a site and vice-versa.)

An article that will help you get started with HTTP::Recorder may be found here.

HTH,