I've just spent the last hour getting rid of someone who was stealing my wireless network. A PC Server appeared in my Finder's sidebar. Mounting the machine's C Drive, I saw that the user data was under a name that had nothing to do with any of my friends or family. I changed the password of the network to a stream of gibberish, and changed the encryption key from WPA to WPA2. Within minutes, the PC Server was back in the sidebar. Eventually, I simply changed the access controls to Timed Access, and added the MAC addressed of all devices which would access the network, which seems to have done the trick. To cut a long story short, I have two questions; 1) How was the moocher able to access my network so quickly after I changed the password? 2) Obviously having to authorise every MAC address individually isn't the most ideal solution. Is there any way to prevent the answer to 1) happening again, so that I can simply give the password to visiting friends, without mucking around with MAC addresses?