Storing login and logout time

[eluser]boltsabre[/eluser]
Eh? You want them to login and if it's the first time redirect them to a "register" form... how can they "login" if they haven't even registered yet?

Anyway, I'd just make a "register" form, and when the user has successfully completed this form set a user table column called "fully_registered" (or whatever you want to call it) to 1. When the user logs in just check for this and if it's 1 you know they are registered, else redirect them to the "register" form. Saves on mucking around with dates and stuff, and saves on DB storage (a tinyint(1) is much smaller that a DATETIME column).