No special VPN software is needed; you can use XP's or Vista's built-in VPN capabilities. The service costs $8.88 per month, or is available in one-, three- and seven-day increments for $3.88, $5.88 and $6.88. You can also get more secure VPN encryption from the service for between $10.88 and $13.88 per month.

Once you subscribe, you'll get a username, password and IP address of a wireless VPN server. At that point, you run a Windows network connection wizard, fill in the username, password and IP address information, and you'll be ready to go. In Windows XP, choose Control Panel-->Network and Internet Connections-->Create a connection to the network at your workplace. From the screen that appears, choose the virtual private network connection, and follow the wizard.

In Windows Vista, choose ControlPanel-->View network status and tasks. Then click "Set up a connection or network," and then choose "Connect to a workplace" and then "Use my Internet connection (VPN)." Follow the wizard after that.

Disable your wireless adapter

There may be times when you're at a hot spot when you actually don't want to connect to the Internet. In that case, you can guarantee absolute safety -- disable your wireless adapter so you can't connect.