Posting in case this helps someone. I have been following a few wifi related threads because I had problems with wifi after upgrading to Jaunty.
In the past I had manually setup my wifi WPA settings in the /etc/network/interfaces file. Then I started using the Gnome Network Manager. My manual settings did not cause a problem until I upgraded to Jaunty. Just for the heck of it I removed the manual settings from my file and it fixed the problems that I had.
I know that for some people this is a kernel issue, but for me it turned out to be a problem with Gnome Network Manager not liking my config settings.
If you are having problems and you had previously manually configured settings, back up your current copy and try to revert to only auto settings such as this....
Hope this helps someone.
iface lo inet loopback
iface eth1 inet dhcp
iface wlan1 inet dhcp
Forgot to note this: For the newbies - the eth1 and wlan1 values may be different on your machine. Use the network interface names for your machine.