There can be a simple solutions to this problem. For example, a fixed image can be use. This will be very easy to write in any language. The server admin can make a graphic image of the text he wishes to use and it will never change. The registering user has to type in this word to complete his registration. It doesn't take much to confuse bots. You can even hack the code to say on the registration page "enter the word 'monkey' in the box below to finish your registration. This alone will stump most if not all bots.
