Seems like you posted this at the Ubuntu forums already (without answers so far). Your card should work at least with 2.6 kernel series as far as I know, and I take it that it did work with your previous version of Ubuntu (or whatever you used), right? If it is so, then this might simply be a bug in the driver/some other part included in the beta version of the new Ubuntu. The final version is to be released in a little over a week from now, so when it comes out you can do a full upgrade or reinstall and see if it's fixed in that version. I wonder why you didn't test with the LiveCD before upgrading, knowing that it's still in beta stage..that would have shown you that the wireless doesn't work and you could have waited. I myself haven't upgraded yet because of the nVidia bug, and probably won't before it's settled for good.
Another possibility is that it's just the new NetworkManager that's giving headache. There's a known bug in the beta version, according to Ubuntu's website, that the new NM doesn't like static settings saved by older Ubuntu versions; this probably isn't the case with you, but it just shows that the beta version (and especially the new NetworkManager) has bugs that are hopefully solved when the final version comes out.
If I were you I'd try if the wireless works with a livecd where the potential old underlying configuration files don't cause trouble. If it works, simply remove all your old configuration files and reinstall the necessary packages to get things clean; if it doesn't, you may try (if it's easily possible) to force installation of an older NetworkManager to see if it's that, or even an older kernel version to see if it's a problem in the kernel module your card uses. If the problem persists after the final version of Interpid is officially released, you may file a bug report (you did check the bug reports already, didn't you?)
Last edited by b0uncer; 10-22-2008 at 12:30 PM.