incrediBILL - 8:46 pm on Oct 2, 2011 (gmt 0)

Spambots can easily be stopped with a line or two of javascript in your registration form that counts key presses and sends that count to the server. Spambots don;t press keys, problem solved. The actual key count doesn't matter, just the fact that a key was pressed.

Also, block the ISPs IPs in .htaccess, another simple solution