ctdesignz,
I am not sure what is "special" per-say about Amazon's login - its been a while since I've ordered anything.
There may be scripts available for you to take but I recommend against it, for many reasons..
- You don't know the system in case something breaks
- you don't know if they put in a back door (unlikely, but possible)
- You're using their vision, not yours.
SO,
This site, along with a million others have tutorials on creating a login system.
It usually consists of a Database (often MySQL) to store the records, a php file that handles the checking if they are logged in already (you dont ask them to log in if they already did) and another file that actaully logs you in/out (this can be 2 as well).
I would start with the MySQL PHP tutorials to get yourself well versed in using SQL with PHP.
Once you have done that, I would follow or read a tutorial on making a login system, but be sure to read through what the author is trying to tell you.
If you put something together, you can post it here under Code Critique (if its working) and if you're having trouble, once you have some code we would be happy to help you with any bugs, or suggestions, best practices, etc.
I hope this was of some help, and if you get stuck with any specific functionality you're looking for just ask.