Why dont you make one yourself? There are lots of guides over the net which give you a briefing on how to connect your webpage your SQL DB's. It is a very minor thing and you should be able to get it done.
Try and find a ready made script. That would make it much easier. There are a couple of tools here on the forums that can help you out with what you want. Please search for them.
There is nothing like the basic PHP Code. Search the forums. Long ago there was a registration page made. You could even search google for the rest of code.
This is the server dev forum and not website development. Thank You.