I've tried everything, and there's no way to get online with Airport in OSX. What you could do is try rebooting in 9. That should work for you.
Word is that the 1.1 release (or update 1.0, as they're calling it) may support Airport. But not yet. Sorry, homie.
Have a look over at the forums on http://www.macnn.com. Somebody there has posted a fix to get Airport to work. Lots of people are saying it works for them. But it is only for machines with airport cards - no good for PC cards like my PB Wallstreet :-(
Apple is working on getting AirPort to work... they wouldn't leave out one of their most popular new products on purpose! But remember that this is still beta software... there's a lot of things that don't work yet.