Stop spam from Joomla contact form: Anti-spam by Captcha for Joomla 1.5

After installing a contact form in Joomla 1.5, I recieved lots of spams through "Contact form" in Joomla into my email.
Here I want to share my efforts for finding one of the best solutions for solving this problem.
Officially, I appreciate so much owner of this patch for Joomla at:

All information can be found on this webpage:


My Descriptions:

QContacts is a contact manager component derived from com_contact the standard component distributed with any Joomla! installation.

QContacts offers the following additional features
* More contact fields: Skype Id and Yahoo Messenger Id.
* Up to 6 custom fields can be added to the online contact form. 
* An optional captcha verification image can be displayed to prevent automated programs (spambots) from sending spam email messages through the contact form.



1) Download this ZIP file
2) Install this ZIP file into your Joomla Admin panel Extentions-> Install
3) Go to Components-> Qcontacts and define a new contact. Also for this contact, you can go to EMail Parameters and set "Captcha" as "Yes" with the length of 5 or 6 
4) Go to Menus-> Main Menu and define a new QContact Menu
5) That is all...