Pass variable to another page?

[wendymelon]

How can I pass a variable/value from a page to another page?

Scenario:
I have this user logs into a page.
The following activities will be based on the constraits of the userID.

[Weedpacket]

This is what [man]session[/man]s are for.

[jordy]

Or the simple $_GET vars...

http://nl.php.net/manual/en/reserved.variables.php#reserved.variables.get