I have a tell a friend script in PHP that lets the user completely customise the message sent to people of the email addresses they enter. Because the message can be completely edited and sent to anyone this means that it can be prone to spammers.
I need someone to take this script and just make it so that an automated spammer can't just use it automatically, something like captcha image coding or atleast a ban ip feature.
When bidding tell me how you will do this. This should be a fairly simple project for anyone who has done related work like this before.