Multiple blogs with 1 login !!!!!

Hi,

I have two blogs:
http://mysite.com/blog1 & http://mysite.com/blog2

Currently, when a user registers in blog1, he can use his user/pass info to log in blog2.

My problem is:
when a user is logged in blog1 and he navigates to blog2, he’ll be forced to login again (i guess, its sessions/cookies problem).

Can any wordpress Expert help me how can i share the login status cross multiple blogs in the same domain?

Thanks a lot 🙂