Sharing an unsecured wireless internet connection?

If you have a wireless router, and an unsecured network, anyone can share it and connect while the router is on. You will have to go to your settings and click the options, ie, shared printer and shared folders, on mine (Vista home premium) these options are under "network and sharing center". You can also create a pword. I would recommend setting up a pword that only you and your neighbors would know so either one of you can connect at anytime and be safe. As far as security, I would like to know this answer as well. I have had no problems as of yet where I live. I also would like to know what extra steps to take to keep my laptop secure. Great question!