I've used the same php formmail code successfully on a few websites, but recently got spam from a contact form. I added a fix I found on the forums, which was adding a drop down menu choice, plus using the form verification (forgot to turn that on originally). Then I got another email full of website references. Any other fixes?

At this point, you would have
Andrew, I have been using
Andrew, I have been using this script for half a decade now or more in all its variations.
I like what you've done and every time I find something new I like to share so....
Instead of a captcha, Try adding this: http://15daysofjquery.com/safer-contact-forms-without-captchas/11/
to the form :D