This is a great script that is created in PHP and requires mySql. The script is created by Masuga Design and is a great way to add rating functionality to your site. You can also set the number of rating units you want to use (i.e. 4 stars, 5 stars, or 10 stars) on a rater to rater basis. Note that this script isn’t tied to any specific system (such as WordPress), so you should be able to adapt it to your situation without too much trouble.