maybe jmeter could do it or something like serverside javascript like rhino...but seems you're heading down a slippery slope anyway. make sure you setup your http headers and response codes to look like a browser. but as per my slippery slope observation, these kinds of systems are also usually rigged with a bit of random checks anyway with captcha showing up. in the event someone is watching and doesn't appreciate your automation attempts, they may even start popping up more captchas based on your ip address etc., or could start popping up captchas incessantly if they're really against this...and thus defeat all your coding powers at press of a button.
the hardest line to type correctly is: stty erase ^H
