I have written several articles on wireless security, in fact if you are reading this you most likley know a lot about keeping secure while wireless or setting up wireless networks.
I wanted to pass some more information for when you are on the road. We all know that Public networks is something that should be avoided. You should always SSH back home when on a Public network. We know the reason is because of sniffers but what about our secure web browsing, such as https sites? Well there are rouge AP in Public areas with rouge software on them that log all input into the device. Some APs have been hacked to carry the software and some APs have been loaded with a firmware that is designed to log all input. Take a look at http://packetstormsecurity.org/wireless/wlan_webauth.txt and http://airsnarf.shmoo.com/rogue_squadron/index.html.
We know that even closed APs can be hacked in time. Even if you follow my guides to secure your networks, they can still be penetrated in time. SSIDs are not encrypted, therefore they can be sniffed very easily. MAC filtering can be hacked in time by discovering a clients MAC with tools. WEP is crap, and WPA2 can be hacked, even if you use TKIP and AES encryption – it is possible.
Keep in mind of where you are and what you are doing. Being paranoid is the safest state of mind in Public wireless environments. Always SSH back home or use some sort of tunnel to ensure your packets are not being captured and your input data is not being logged. Wear a condom too, just in case.
EDIT: I forgot to mention that it is a good idea to use OpenDNS when you are on Public and even private networks.