Wi-Fi Security

I just got myself a new laptop computer and decided to do a little research about wireless networks in San Jose. Before I left my friend's house I grabbed a free program called Netstumbler (http://www.netstumbler.com) that does what the name suggests; it searches for wireless networks in the area. As Netstumbler finds a network it logs it in a clear easy to understand list complete with SSID (Name of the router), Channel, and whether or not it is encrypted.
Within a quarter mile of my departure I immediately had stumbled across at least 25 different wireless networks. I continued from downtown San Jose towards my neck of the woods in Almaden driving on the free way and eventually wound up driving in my neighborhood doing the same thing. I was surprised that even while driving on the freeway a bunch of wireless networks kept popping up. I don't think I went 100 yds without something popping up. A few of the interesting SSIDs that I ran across were: Best Buy, Geek Squad (a division of Best Buy), and a very interesting one indeed Sj-Free-WiFi. Over all I found 233 wireless networks in a 9.6 mile drive (give or take a mile from me driving around my neighborhood).
The big question is, why is this important? Of those 233 networks I found, 89 of them were unencrypted. That means that pending the right distance, I could have logged into any one of these 89 Wireless Access Points (WAP) and used them for whatever reason (except for those set up by business that know what they are doing). I even went down the street from my house and logged into someone's network and turned on AIM just to do some sort of test. I even surfed the internet and was able to do a bandwidth test to see what kind of connection was being run.
Now, the truth is that seeing all those unencrypted wireless networks scared me a little bit. I realized that it's far to possible for someone to come in and do malicious things under your internet connection, and then they can potentially disappear and leave you to blame for illegal activity. I felt a little guilty for stealing someone's internet and logging on to AIM with it because it was just that easy to do.
The point is that people need to be aware of this. If you have a wireless router, make sure you add WEP encryption to your wireless router. Instructions on how to do this are readily available either in the instruction manual that came with the router, or can be easily found on the net. Set your WEP encryption to either 64 or 128 bit encryption. From there all you have to do is make sure that anyone using your router wirelessly has the WEP key on their computer so they can log into the router. A second and very important thing is to change the password of your router. By default many routers have passwords like: admin, and password set as the default password for the router. This can also be potentially dangerous. Anyone that is aware of these default passwords can have a lot of fun messing with your connections, and can temporarily shut you out of your internet access.
In short, secure yourself and your internet connection. War-driving (the act of driving in a car, and then hijacking someone's wireless internet connection to do illegal activity) is becoming more common today. My little escapade I did at 1am doesn't account for much, but someone with much more malicious intent can do far worse than log into AIM.

*EDIT* July 12th...
Looks like i'm on top of it. I just got my latest issue of Winxpnews (Http://www.winxpnews.com) and it looks like they decided to tackle the issue of wireless security as well. It really makes you realize that this indeed is quite the interesting problem.