This post has more advanced considerations than the ones in my last post, but still things I think everyone* should read. Computer security isn't his job in the airforce; he's just found things out by reading a lot and paying attention.
"
Building Peace: It's a dangerous cyberworld out there"
For more advanced reading, the discussion and comments at the end of his post have lots of interesting pointers.
* Naturally everyone means everyone I know who doesn't already know how to use a packet sniffer and/or hasn't reconfigured their wireless router.