I'm sure you could find good resources using Google and searching for "PHP 5 star voting" - have you tried that?
Consider my wrist duly slapped.
Yes, Google is an excellent resource, although in my experience for many things such as this a search will return 101 different ways of doing something, many of which will do, or explain, 80% of what you need.
So sometimes posting on a forum is better for getting a recommendation from someone for a good tutorial on something.
Sure - posting on a forum is always better. But with a question like this, you are also likely to get 101 different ways of doing it as well! No wrist slap was really intended.
When I did that search and looked at the first 5 hits, it seemed that the answers were spot on for you.
True enough. I think that it involved introducing formulas made it a little daunting, but looking at a few sites, it hopefully isn't too complicated.
First step I guess is to create a ratings table, get that working, and then get on to the calculations part.
Let us know how you get on, please.