securing a page

[pug]

Ok I have secured it so the user has to login with a username and password that is in the database

I want to allow them to change their user profile such as:

password
fullname (displayed name)
etc..

I am passing on the main page after they log in their userid to the profile page so they can update it. I know how do this BUT I figure if you just put in the id in the address bar and such you could edit someone's info

How can I secure this easily? I know I"m going to have to learn how do session and such....Please help

http://pug.shacknet.nu

you can test it out...the update user profile page isn't finished that is why i'm asking

[TTT]

put user id in cookie, i have done like this when user log's, logged user information goes to logged_users table, everytime when user refresh's index page action time goes to table, you only have to set cookie to client:

setcookie ("CookieName[userid]",$user,"","/");

[pug]

Are there any other ways to do it?