AirPort Express as a wireless bridge?

I am trying to set up my AirPort Express base station as a wireless bridge to my B&W on a network with a Linksys WRT54G router. I know that Apple says that AirPort Express only works as a bridge when networked with an AirPort base station, but I have heard from several places that it does indeed work with my specific router. I have found sources like this one that confirms that it will work, and it even gives a brief overview of how to do it. However, I have been unable to find any specific instructions on how to make it work. Can anybody give me some tips, or help me out with this? I would really appreciate it.

I am trying to set it up so that I can connect it to the B&W via ethernet, and be able to connect to my home wireless network through it. I'll try the instructions in the link provided by Steven1621 (thanks, by the way), and I'll post back here and let you know what happens.

I can't get the firmware upgrade to work. Each time I select the file and click upgrade, it shows a progress bar across the bottom. After the bar goes all the way across, it shows a message that says, Please wait! Setup will take a few minute, and it continues to ask for my name and password every 30 seconds or so. It doesn't seem to be doing anything.

Okay, I finally gave up on the firmware update, and I decided to go on without updating. I followed the instructions in jsw's post exactly as they were given (with the exception of the firmware update) and it still worked beautifully! I don't know how it worked without the firmware update, but I'm not asking questions at this point. Thank you all so much for all of your help. I couldn't have done it otherwise.