What is vBulletin?
vBulletin is a powerful community solution that makes it easy to add a forum messaging system to your web site. vBulletin is developed using PHP and MySQL (a highly efficient open-source database). This solid back end technology allowed us to develop a product that is both amazingly fast, yet reassuringly stable.
System Requirements
Minimum
PHP 4.3.3
MySQL 4.0.16
Recommended
PHP 4.4.2 or 5.1.2 or newer version
MySQL 5.0.19 or newer version
Operating System
» Solaris
» Linux
» BSD
» Windows™
» Mac
Preparing
1 . Go to members.vbulletin.com. Login with your "Customer Number" and password.
2. Download the last stable vBulletin version. From the zipped file extract the "upload" folder. The "Upload" folder contains all files needed vBulletin to work.
3. Rename "includes/config.php.new" in config.php. Open config.php with some PHP editor. Change the settings for databese, mysql username, password.
4. Upload all vBulletin files to your server.
Installation
With your browser go to http://myforum.com/forum/install/install.php.
* Change myforum.com with your forum url.
1.Enter the "Customer Number".

2. If everything is fine, the installation should begin.

3. "config.php" is being read.

4. Connecting with MySQL database...

5. Now, just click on Next Step button, so the writing to the base can begin.
6. When you come on 9th step, stop! Here enter the name of the forum, the link to the forum, email.

7. Make the first administrator account.

8. Now delete "install.php" from "/install/" folder.

9. Finally, vBulletin in installed.

10. Of course, vBulletin come with Administration Control Panel. You can access AdminCP with http://myforum.com/forum/admincp

I hope you like this tutorial. :)