Public Wi-Fi: Be Very Paranoid

Here are some tips from an old but very informative Businessweek article on protecting yourself when using public WiFi -

Use a virtual private network (VPN). If you don't have a VPN option, seek out secure Web sites that encrypt all traffic. You can tell a secure site by an address that begins "https:". If you use Firefox, a secure connection will turn the address bar gold. You can generally use these sites with confidence even on an open network.

But if you are visiting an insecure site, and that includes popular mail services like Gmail and Yahoo!, an eavesdropper will have no trouble reading your messages. If the login page isn't secured, your password will also be exposed. So don't use a password for a Web mail account that you also use for online banking or anything else where privacy matters.

Don't use an open connection, either. If the network is legit, connecting sans permission may be regarded as theft. Worse is if you end-up connecting to a rogue network that steals your data and infects your computer. Be leery of "ad hoc" networks as these are highly likely to be rogue or infected systems that will damage your system without ever actually connecting you to the Net.

While public wireless networks are immensely useful but the dangers are real, and simply understanding them will go a long way toward keeping you safe.

Source article here.