WordPress MU

is there a way to disable username only on registration, as I want new people all to have a blog? thanks

Looking at current wp-signup.php file, I'd remove between lines 258 and 270. That's the form that allows folks to choose as to what they want. (It's wrapped within p tags.)

Then to force the signup, take a look at the function validate_user_signup() shortly after that. See lines 292 to 295? I'd just remove everything but the following:

signup_blog($user_name, $user_email);

That should work.