WiFi security or lack thereof (Part 1)  This is an excellent article on securing a wifi network.  I cannot tell you how many wifi networks are unsecured, or only partially secured in my own neighborhood.   The very first thing you should do when you log into your wireless device is change the default password!!!  Change it to something only you can remember!!!  Do NOT make it the same name as the router.   You want to make sure and turn off DHCP.   Turn off broadcasting your SSID.   Turn on some form of data encryption.  Make sure you use the MAC Filter.    The above link goes into detail on how to do all this.