LinuxQuestions.org - centralized authentication

I'm not the most experienced Linux person, mainly because I've fallen into the trap of SuSE and it's easy admin tools.

I have a few (6 or so) Linux boxes on my network. I would like them to authenticate (user and group lists and passwords) from a central source. I have a machine ready for the task.

1) What system is easiest to use in a multi-distro environment? I don't need directory information features and all that, just users, groups, and passwords, and also centralized storage of permissions (i.e. I create a user called "webmaster" on the central server that automatically has access to /srv/www on every machine that has that). I also need to be able to assign rights on a machine-by-machine basis. I.e. user "sunadmin" has full priviliges of a certain group on a machine called "sun" but not on a machine called "moon". I have mainly SuSE Linux right now, but also plan to try *BSD, OpenSolaris, and CentOS. I need something that will work with the majority of them.

2) I would also like something that is relatively quick to setup on new machines.

3) I need some level of backup on each machine at the local level. It's ok if nobody but root can login if the auth server is down, but I need system services/users such as wwwrun to continue to function.

****Lastly, and most importantly:
I've never worked with anything like this before. I really need a recommendation of a good book or web site that can walk me through every step of configuring this and setting up user permissions.

I tried both LDAP and NIS. I got the LDAP server working but couldn't figure out the directory scheme. I figured out how to get NIS to serve authentication information, but couldn't get it working.

Thanks.