Hi All, I found a solution for Ubuntu 9.10: do a fresh install of Ubuntu 9.04, then upgrade to 9.10 via the Update Manager's "Upgrade" button. Then wifi is happy.
So, yeah, I also have a Dell m1530 with the Dell wireless hardware and experienced the same issue (no wifi light, no recognition of wifi hardware) after a fresh install of Ubuntu 9.10 (Farking Koala). Even adding the 'noapic' boot time kernal parameter did not help.
The Dell wifi hardware works fine in Ubuntu 9.04 (Jiggly Jackelope). If you *upgrade* to 9.10 instead of fresh install, the wireless functionality remains.
My guess is this somehow has something to do w/ the bootloader setup? (Koala uses grub2 and it's all moved around???).
Anyway, hope this helps those of you tempted to give up on Ubuntu over this. After many turbulent years of linux use, I've finally made made the switch to linux as my primary personal OS thanks to the leaps and bounds in usability Ubuntu has made.