I've used a generic flash/php contact form on a new site but the webhost has told me it's open to spamming. Is there any way round this? Is there a PHP script that is safe to use?

Thank you so much. I put it here:
// Print this only when there aren't any more entries..
if($_GET['NumLow'] > $numallComments) {
print 'No More Entries!&';
}
break;

case...

I have set up a guestbook on a flash site and the customer has asked for a bad word filter to be incorporated. I have this code for it:

$bad_words = explode('|',...