Probably just that easy, but keep in mind when you join a network outside of your own house, like in Mickey D's, or a hotel, you are now on a local network with a bunch of strangers. That's all fine, but make sure your laptop is sharing any files on the local network. It most likely is not, unless you set it up to do so.
Probably not a bad idea to make sure a firewall is running on the laptop too.
Here, BTW, is a transcript and audio from the "Security Now!" podcast on the very subject of public WiFi and security. This is a good podcast on the various issues of computer security.
That's all fine, but make sure your laptop is not sharing any files on the local network.