I used the opportunity while I'm here in the U.S. to go buy a cheap WiFi networking card. There's a deal at Staples right now for a Netgear MA401 802.11b wireless networking card for $55, with an extra $20 mail in rebate. That's $35 for a WiFi card that'll cost me at least $95 in Spain.
I was chatting with Jim and Erik briefly just now and Jim gave me a great link to the Airsnort homepage - which is a wireless sniffer. I can't wait to try it out and see if it'll work with this card...
Anyone else know of any neat software for WiFi?