building a webite question?

well depends on how you want to access the data and display it, what sort of hosting you have.. you could look at eg -> http://www.wikihow.com/Create-a-Secure-Login-Scrip...

since something like what your asking isn't a easy path, just wondering why you didnt google this issue/query first.

You can install Wordpress or Joomla and look for a theme and some plugins will make your job done

as a beginner use a Database to store the username and pass make sure you encrypt them..

while you click login, the username and password should be searched in the DB using a query

if correct go to the user page

else trow an error

this is most simple method

as Paultech said, why didn't you google it?..................................................... or yahoo it?

You can try the Html Code or try bravenet.com or poppydog.com or wildapricot.com

encrypt passwords with md5 has, etc to make it secure.