If it's broadcom, see if ndiswrapper supports it, it probably will.
There's detailed instructions in the ndiswrapper wiki for identifying your chipset correctly so you can get the correct driver, and there's a walkthrough for installation and setup. It should work for you, it works for me, i've got a compaq presario r3000.
I ended up using the bcmwl5a driver off the cd that came with the computer, which isn't recommended, but it works well, no probs so far.
Here's the url for the wiki, so you don't have to waste valuable time looking for it:
EDIT you may also find this useful