post an output of* lshw -C network* from your ubuntu terminal

This wi-fi card does not appear to have a Linux option

Well, here's another oddity--Ubuntu 8.10 recognized it without any problem! Any
ideas as to what's going on?

Unlike Windows there aren't external drivers for most things. So you don't
have to search for drivers and insert disks as in Windows. The detection is
done by the kernel and the drivers are supplied either at that level or with
the distro. Ubuntu 9.04 uses a different kernel from 8.10 and Canonical must
fit everything onto a CD.

To keep things from ballooning things are pared down and decisions are made.
Sometimes things are left out by design and sometimes it is an oversight.
Otherwise things would swell to unwieldy proportions and people would
complain. Different versions mean different decisions were made. There is no
way of knowing whether your hardware was an oversight or a deliberate
decision. You can't please everybody. They get complaints either way.

There have been ongoing discussions about Ubuntu moving to a DVD, but so far
they have resisted. At some point tough decisions will still need to be
made.

So what you're saying, in effect, is that I need to go back to 8.04 to be able
to use my wireless card? Are there any alternatives you can suggest?

Im a bit late on this thread but try this link:
ubuntuforums.org/archive/index.php/t-944.html

Its a older thread but it talks about the drives here.

And this link:
http://www.marlow.dk/site.php/tech/madwifi

Unfortunately, both threads are old enough that I'm not exactly comfortable
trying them. Sourceforge has a "madwifi" package available for download, but
without up-to-the-minute instructions, I'd be hesitant to try it! Does anyone
have any such info?

I was only answering the question why there was a difference. I am not
suggesting that it is necessary to go back to 8.10 or 8.04.

Not everybody should be running the latest version. 8.04 is an LTS release
meaning it is considered stable and has long term support. This is for
enterprise people who do not like surprises and want a rock solid system
that just works. Many newbies should stay there until they feel comfortable.
Six month releases are not considered as stable. There are significant
changes that can give headaches.

Consider when Windows Vista came out and the law cases that ensued due to
failed promises of being Vista ready or capable. You see nobody can
guarantee that an upgrade will mean all of your hardware will work, even
Microsoft with all of its connections to hardware vendors and money to burn
has problems. In contrast open source relies on good will of vendors as it
has no special relationship. It is hard to dot all of the i's and cross all
of the t's. These people try their best, but sometimes things don't work
for various reasons.

My advice is for new users to choose the LTS as their entry point. Then be
ready and willing to learn. As they do they can move up to more recent
releases. Even veterans have problems. I get breakage all of the time. The
difference is they know how to resolve them or are willing to do some foot
work to find out how to fix it. In rare cases there are no solutions.

There was a major shift from 8.10 to 9.04 that caught many users off guard.
They were not sufficiently informed about what was new and how this could
affect them. When they jumped in with both feet they had problems. The
problem for most people was with graphics. There were also some overlooked
networking changes from 8.04 to 8.10 and to 9.04. They were subtle, but
significant.

Wireless problems are the easiest to resolve in many ways due to the
existence of ndiswrapper and ndisgtk which enable you to use your Widnows
driver in Linux. This is not the best fix, but it should work provided you
can locate a Windows driver for your card.

I think Ubuntu 9.04 may have the ath5k atheros driver which is not as
compatible with older chipsets.

So you may have to blacklist the current driver in Ubuntu 9.04 and build
the older stable version for the madwifi-project.org website:

http://madwifi-project.org/

I had to download and install a replacement ath_hal module to get the
Atheros card working on my wife's HP laptop. She is running Ubuntu 8.04 and
here wireless card does not work with any of the std Ubuntu kernels.