If you are getting a lot of spam in your contact forms, check out the following image form verification: http://www.reconn.us/random_image.html

This is most likely the best image verification example that I have come across. There is one problem though, it is not vision accessible. So what I suggest, next to this image add a link ‘vision impaired users click here’ and open a new window that looks something like the following.

[PHP]
function AddSpaces($str) {
return $str[0].’ ‘.$str[1].’ ‘.$str[2].’ ‘.$str[3].’ ‘.$str[4];
}
session_start();
[/PHP]
… HTML …
Verification code: [PHP] echo AddSpaces($_SESSION['image_value']); [/PHP]
… HTML …
Hopefully this will come in handy for you as it has for me.