Help! Need registration like non-multi-site

I’m kind of desperate here. A client of a client wanted a fairly good-sized WordPress installation done, with the main site and 26 sub-sites. So, I got all that setup just fine using WP 3.01, and I’ve spent a lot of time at it.

Here’s the thing: he’s throwing a temper tantrum because when someone registers for the site, they have to wait for a confirmation email. He wants them to be able to register and have access right then. I know this is possible in WP without the multi-site function. What can I do to get that to happen in 3.01 multi-site (networked)?

Thank you.