PHP session expire?

The only way I can think to accurately describe what I want, is to compare it to ColdFusion, so please bear with me for a second here...

In ColdFusion, there is a "session expiration" option. I can track users (i.e. if User A is logged in, maintain their shopping cart, etc), via server side session variables for however many minutes I specify in this option. It's a setting in the ColdFusion server software that I edit via the Administrator.

Is there a similar option for PHP apps? And if so, where is the setting?

Thanks.