Web2 Style Contact Form with Captcha

This a small and powerful -all in one file- contact form, which is protected with a random colored captcha. There is no need to extra fonts, images, backgrounds etc. You can start to use it with changing just ADMIN_EMAIL. You can easily add-remove contact fields like name, email, homepage, phone number, fax, address, subject, message etc. You can easily set required fields, which visitors must fill. Required fields are red marked when visitors try to send form with empty values. It is flexible; you can change filename or include it in your cms modules. Because of more security it uses session for validation not cookies. There is also a small brute-force protection included. A small donation or backlink wished but not required.