The Scenario A single domain with different platforms located on different subdomains, i.e. joomla.example.com + wordpress.example.com + phpBB.example.com -- and with the way things are organized and set up for this particular community that this domain serves, having, at some point in the future, a "wordpressMU.example.com or wordpress.example.com/wordpressMU" might be desired as well. And yes, there are specific reasons for wanting both. My experience I'm still a beginner with PHP, as I havent really spent much time studying it, although I learn this sort of thing fast, and feel pretty comfortable with the basic 'feel' of the language, having worked quite a bit with Wordpress conditional tags/ template tags + rudimentary custom scripts (like 4-6 lines, or something) So the point being that this is important enough so that the basic process is explained, it will be worth it for me to go learn what that means, what the different terminology means, and learn how to do it + implement it. So I'm not necessarily looking for some pre-made script (although that would certainly be nice), or a beginner, idiot-proof solution. I'm looking to actively start learning PHP here, so simply an overall outline of ways in which this could be accomplished would be great. I.e. "To do this part, you need to set up a so-and-so variable and pass it to so-and-so script via a so-and-so" I probably won't know what this means, but it will still help a lot. What I'm Looking To Do - Have it so that people only need to log in once to a single, centralized script, and then this single script will handle logging in for joomla.example.com, wordpress.example.com, etc. When this centralized script is logged out of, then obviously it will no longer handle logging in to the other sections. - Being able to have a front-end registration section for this single, centralized login + a back-end to approve people, set some basic options, basic management, would be nice, but not essential. - This particular community is small enough so that manually imputing data for each individual person would not be too big of a roadblock. - It would not necessarily have to be integrated with the different sections, i.e. integrated into the scripts behind wordpress.example.com. All it needs to do is be able to pass a user-defined username and password to each of these sections when they go. On the backend basically be the same as if they were logging into each of these individual sections manually.... except I want PHP to do it automatically for them, if they are logged into the single, centralized login script. So this 'language' below is crude & probably not all that accurate, as I'm a PHP neophyte, but its the best way I can think of to illustrate: ---------- PHP global login script is (user logged into centralized login?) if yes{ fetch stored, user-defined, user/pass-data for 'global use' (ideally, the user would be able set this in their little 'profile' within the global login script page) else { then do something else... dont fetch the data} is (user trying to access one of the pre-defined sections i.e wordpress.example.com?) if {logged into global login and if {url person is going to = wordpress.example.com then {automatically submit the user-defined user/pass for wordpress.example.com, stored in the single global login, to wordpress.example.com/loginscript.php or if {url = joomla, then automatically submit the user/pass stored in global login under 'joomla' to joomla.example.com/loginscript.php else if not logged in to global {then do nothing, i.e. present normal wordpress.example.com login page, or whatever. ---------- As I learn & get better at PHP, I'll be able to modify the login scripts for wordpress, joomla, etc, if need be. However, as said above, its not necessary to integrate the global login script with the wordpress/joomla/etc login functions. However, if this isn't far more difficult than making a basic global login section, any outline for the basic process on doing this would be appreciated as well, as I may need to do it as some point in the future -- and it will also be a great assist in the learning process. ---- Thanks in Advance!