First off, it is frowned upon to bump your own thread within 24 hours. We are a worldwide community here, so some folks have been at work/school/asleep while your post has been waiting.
Your question is also not very clear. What are you looking to do? Do you have both a computer and an access point, or are you looking to turn a computer with both wired/wireless cards into a router/access point?
The title of the tread seems to indicate you want to put this device between your computer and the access point, so the device receives the wireless signal from the access point, and delivers it to your desktop through the wired card?
The first technical thing to look at is why bother? You can get a wireless network card for very little money. If you are in the US, go to http://pricewatch.com
and search for wireless G network card. Also check the HCL here are linuxquestions so you know the card will work. You can get them for around $20. If you're not in the US you still probably have access to cheap cards, at least cheaper than an unnecessary piece of equipment to connect.
It is possible to set up WAP54G linksys APs (older versions) as linux based units, but the recent version 5 cannot work, as they shrunk the memory by half. Still, that device is twice the cost of just a wireless card.
You can build linux routers out of PCs, I did that with my very first box. I would expect it would be possible ot make a bridge, but that might get more complicated. All you need for the router are the dhcpd program, some forwarding on the network card, and firewall rules to keep things safe. Not sure how the bridge would go. Probably something similiar, but I'm unsure.