if no www. my site sends visitors to wp-signup.php

Hey everyone,

I'm stuck with a bit of a problem here. When visitors got to http://www.turnystudios.com they get the homepage of my site but if you go to http://turnystudios.com then it re-directs you to the wp-signup.php page.

How can i fix this so the regardless of it going to http://www.turnystdios.om or just http://turnystudios.com it goes to my home page and not my signup page.

Also, I should mention that I am running wpmu with subdomains.