Combining PHP logins... please help!

[mishiwinks]

I have PHPBB, PHPAuction, OSCommerce and Photopost, all with MySQL... and at this point there are 4 registrations and 4 logins. This is crazy, I want to make it where they only have 1 registration and login but have no idea how to do it. I found a mod that allowed me to combine the PHPBB and PHPAuction but they have to register in PHPBB first in order for it to work, and then they have to login to PHPBB and then go to PHPAuction for it to work. If they try to go to PHPAuction first it will just reset the login page over and over, with no response.
Please tell me someone is the smartest person I have ever met and knows how to do this.

[nemonoman]

You have installed 4 different programs, each with its own log in method.
You will need to modify 3 of these programs.
Choose the simplest/most used program in your site, and use that method for the log in for the other 3. You'll need to modify the 3 to look at the 1st programs user table instead of their built-in tables.

Find the parts of the 1 program you like that
1 check to see if the user is logged in
2 present a log in screen and submit data to a user table.

Then look for the similar parts of the other programs.

You probably don't need to alter the look and feel parts of the other 3, just the parts that manage user log-in status internally: for example, just by changing the names of the tables being used.