One of the most frustrating things about running Ubuntu, or for that matter, any Linux based operating system on an older laptop is the fact that many wireless cards simply will not work.
This is because many of the companies that make these cards think that open sourcing the drivers needed to run their equipment will give away trade secrets. In addition, in some cases it would be possible for developers to change frequencies of cards, allowing them to operate out of band. Thus, most of the code for the drivers needed to run these cards has been kept closed. A few linux developers have been keen enough to crack drivers open and write there own code.
There are software packages available the act as a wrapper, and run the Windows version of the driver within Linux. The most popular package is called ndiswrapper. This nifty little tool can be downloaded from the Add/Remove Software tool from within Ubuntu. Then, it is a matter of popping in your wireless card driver disk, and making the following menu options: System -> Administration -> Windows Wireless Drivers. From there you would select the correct file from your card's CD.
You can find cards available that run in plug n play fashion. There are some Broadcom cards that are available withing the default Ubuntu 8.10 distribution. Another option is to use a wireless USB card like the Wireless G USB Adaptor from Belkin.
Or you can pick up a nice shiny new Dell Mini 9 inch netbook with Ubuntu pre-installed. Droooool.....