ready to go authentication script?

[sid]

ok... i run this web community ngoy.net which has been around for a year and a half now and has about 4000 members by now.
it features all kinds of functions, some of them are accessible to members only, others to the public, and some have increased functionality for members.
ok - i have been working with a self-made authentication script, and it has been working pretty well... i am planning on redoing that whole thing now and revamping the code. for this i am finally looking for a tighter authentication sysem that allows me to ad more functionality. so i wanted to check if anybody could point me to a free script that should feature the following:

• multiple levels of authentication (min: 3)
  ie something like that:

  if (authenticate_function(2)) {
      print "your userlevel is 2 or higher - flip and yell yahoo!";
  }
  else {
      print "you are not entitled to view this page";
  }
  

• put a username in a variable/constant
• put a user-id in a variable/constant
• simple inclusion in an existing system

thanks in advance fr any help - i did some research but seem not to be able to evaluate what would be suitable for my needs - so maybe you could help me out with your ideas!

[mystrymaster]

honestly I would think you should do it yourself that way you can add the exact functionality you are looking for - there are some that do about what you are looking for in the code library here though.

[sid]

cool... thanks... any experience with authlib 1,96?