[AjaxM]

By AjaxM - Introduction to database (Basic)
By Faraday - Basic MySQL Tutorial
By Overhaul - MySQL Registration System [Threaded Queries + Whirlpool]
By Jarnu - Setting up MySQL database [For newbies!]
By newbienoob - MySQL Registration System [Threaded Queries + Whirlpool]
By Overhaul - Using BlueG's MySQL plugin R7 and newer (with cache)

You should be good to go with the above links.