I have an Airport Extreme card for sale. This card is suitable for Macs that are Airport Extreme ready:
http://docs.info.apple.com/article.html?artnum=107440

$60 if you pick it up (Shenton Park), or $70 and I will post to you in an Express Post bag.
Please email me off list if you are interested in buying.

It is *not* an Airport card: http://docs.info.apple.com/article.html? artnum=106777

If you have an Airport card you want to sell, I will buy it from you, or swap it for the Airport Extreme card.

Regards,

Glenn.