W3C mobileOK Checker
http://validator.w3.org/mobile/
Data Filtering Using PHP's Filter Functions - Validation
http://devolio.com/blog/archives/413-Data-Filtering-Using-PHPs-Filter-Functions-...
Speed/validity selectors test for Javascript frameworks
http://mootools.net/slickspeed/
Javascript Form Validation with standalone, jQuery and Prototype plugins
http://www.benjaminkeen.com/software/rsv/
Ultimate PHP Form Validation
http://www.benjaminkeen.com/software/php_validation/
PHP Validation of Phone Numbers
http://benramsey.com/archives/making-it-valid-telephone-numbers/
PHP - Validating User Submitted Data
http://www.php.net/manual/en/security.variables.php
RFC 822 Email Validation
http://iamcal.com/publish/articles/php/parsing_email
Form Validation by Apple - Javascript
http://developer.apple.com/internet/webcontent/validation.html
Dynamic JavaScript Form Validation
http://www.leigeber.com/2008/04/dynamic-inline-javascript-form-validation/