Logingin with same username and password from two different forum

[Mc_Bozo]

Hello.. I want to ask questions which i need urgent answer.
I have two forums installed on two different subdomain and i want my users to login to both forums with same username and password. What i mean is that:
sub1.domain.com login: (username - password)
sub2.domain.com login: (username - password)

Waiting for your replies, i need it urgent.. Thanks..

--------------- Added [DATE]1255239365[/DATE] at [TIME]1255239365[/TIME] ---------------

I'm still waiting reply.. Please i need it so urgent!