This nice and simple script that uses regular expressions to check that a form field contains a valid email address.
Developer: DynamicDrive.com Platform: Date upd:2005-11-12 Hits3385 [Visit]

With TSPHPFeedback you can insert contact forms on your web pages, that doesn’t requires to reload the page to open the form and send the contact message, due an Ajax based implementation. This script is packed inside a Dreamweaver extension, you don’t need programming
Developer: Trio Solutions Platform: linux, windows, freebsd, osx, sun Date upd:2007-03-18 Hits2366 [Visit]

Bots and spam mechanisms are capable of picking email address up from HTML source code - Use a Javascript to form your email addresses and kiss spam bots goodbye.
Developer: designplace.org Platform: Date upd:2003-02-12 Hits3291 [Visit]

This script encrypts any email link on your webpage to hide them from harvesters and spammers. The script shines in its ease of implementation and extensive browser compatibility.
Developer: Dynamic Drive Platform: linux, windows Date upd:2005-08-22 Hits2445 [Download] [Visit]

Simple cut-and-paste boilerplate script solves a common problem with bad e-mail address entries on forms. The script checks e-mail addresses for all common entry errors using powerful regular expressions. This short, easy, reliable script double-validate e-mail addresses with entry and confirm-entry boxes. Can be
Developer: codelifter.com Platform: Date upd:2004-03-05 Hits11670 [Visit]