Adding server side validation is quick and easy using this PHP form validation script. All commonly required form validations are provided. You just have to mention the type of the form validation.
Contact Form Killer is a nice little tool you can add to your web site to easily generate contact forms with all that messy form validation already taken care of for you.
The Form Spam Blocking Script will block form submissions that include user defined blocked words, effectively stopping all form spam including automated scripts and user submitted data.
Stores private data and fills web-forms automatically. Reproduces order of clicks on web-links. Possibility to edit forms without page loading. Subject profiles, intellectual bind of user profile fields to the fields of online forms.