Two options;
1) The Avaya ORiNOCO Ethernet Converter £185inc VAT, but you also need to buy a PCMCIA Wireless ethernet card, cheapest approx £60.
http://www.expansys.com/product.asp?code=OR_848333423
2) The better (or cheaper option) £148.04 for the Linksys WAP11. I haven't proven this yet but apparently via a Firmware upgrade you can turn it into an Ethernet bridge.
http://www.insight.com/cgi-bin/bp/948139012/uk/result.html?t=A&a=s&f=p&d=WAP11
http://www.linksys.com/download/vertxt/wap11_fw_ver.txt

Dobbs