I've developed another email address encoding function in PHP. This works on a similar principle to the well-known HiveWare javascript encoder, but doesn't require javascript to be enabled on the client. Instead, this PHP function just needs to be included in your web page, and then where it is called it will write out an encoded version of your mailto link. The CDT; has reported that encoded email addresses have been effective in preventing spambots from finding addresses on your web site. The function is provided and described on my web site: PHP Email address encoder.