Setting session expiration?

[laredotornado@zipmail.com]

Hello,
I am having trouble with PHP 4 on Mozilla/Firefox. How do I set
the expiration date (within my PHP code) for the cookie created by

session_start() ;

I tried

session_set_coo kie_params(time () + 3600);
session_start() ;

but when I check Firefox's cookie settings, it says my cookie is set to
expire at the "End of Session". Shouldn't it say a time? Any advice?
- Dave