Originally Posted by http://gentoo-wiki.com/HOWTO_setup_a_gentoo_bridge#The_Gentoo_802.1d_Bridge_Guide

Creating 802.11/802.3 Bridges

Quite simply, Linux does not support this easily. From Jean Tourrilhes' site:
The conventional Ethernet bridging method (promiscuous sniffing) doesn't work with most wireless LAN standard, because of the header encapsulation and the interactions with link layer retransmissions. In other word, most often, when you use a software bridge on a wireless LAN (such as the Linux bridge on a 802.11 card), it doesn't work (moreover, quite often promiscuous is broken as well).
The driver could work around this restriction by creating its own MAC headers (802.11 headers instead of 802.3, and putting the right bits in the right place), but in fact most vendors don't provide the specification on how to this with their hardware (when they don't explicitely prevent it in hardware, to force you to buy their Access Points). (http://www.hpl.hp.com/personal/Jean_...ess.usage.html)

The eventual goal is to bridge a wireless network to a wired network. Fortunately, this is exactly what an access point does. There are several out there from which to choose. If you have lots of money or need VLAN/QoS support, the Cisco Aironet 1100 and Aironet 1200 access points are a great investment. If your budget is more of a requirement, the Linksys WAP54G or WRT54G are cheap and quite effective. (The Linksys Cable/DSL "routers" can easily be turned into a regular access point via a single selection box in the configuration.)

So rather than trying to hack a Linux 802.11/802.3 bridge together, spend the $100 and save yourself a lot of headach