For the software.
First we will start with a basic operating system. Most people will use Windows. I prefer Windows 2000 because I change hardware alot and don't like to have to notify Microsoft that I have done so. XP will sometimes stop working or work in a limited fashion if you switch hardware enough from the original install. So get a copy of whatever your prefer to use. Make it at least Windows 2000 or XP. Windows NT 4 can be used, but I would only do so if you have really low end hardware. This will add anywhere between $100 to $200 to the cost depending on what version you pick.
Next:
After installing all the software and drivers for your hardware and updating the patches you will need to search for your free sniffer software.
The first thing we are going to do is install WinPcap 3.0 This program allows you to capture and read internet traffic. Get it here and run the executeable.
http://www.ethereal.com/distribution/wi ... ap_3_0.exe
Next we will install ethereal for windows. This alows you to look at network traffic in real time and capture the traffic to a file to be looked at later. (with winpcap installed)
Click here and install.
http://www.ethereal.com/distribution/wi ... 0.10.8.exe
Next check out the online documents and read about what you are going to do and the best way to sniff for "terrorist communication" at home or at your school.
http://www.ethereal.com/docs/user-guide/
When you run ethereal and capture the packets to a file you will se run in its raw state that it makes a pretty big file in a short period of time. Now imagine that on the trunk of an ISP you have to filter to look for "key" words to capture in your packets. This will still produce a big file, perhaps too big for the FBI's IOMEGA zip disks...this is where I think we get the term "chatter". The FBI gets too big of file to look at, so a report on the file size made by the key words and phrases in online activity is looked at.
A big file means "increased chatter" and the useless terror alert color goes up to Orange. A smaller file means "reduced chatter" and Tom Ridge pats himself on the back while not taking into account the FBI's recent problems with computer upgrades on the Tsunami wiping out a good deal of infrastructure in Norther Indonesia.
Anyway now you too can have your own "terror alert system" installed that will probably be about as useful and alot cheaper than the FBI's.
When the FBI ditches Carnivore, it will move on to something else. I am guessing it is going to be something like SNORT
http://www.snort.org/ but instead feeding info to an online database (probably Oracle) with encryption hiding the traffic. This too can be easily made with one computer but for more accuracy you could use two. Get a friend to help and each set up a Snort computer with a mysql database
http://www.mysql.com/ then you can set up a VPN tunnel to one anothers computers to use the data bases.
Then you have a WHOLE ANTI-TERRORIST CRIMEFIGHTING NETWORK!!
At home and really cheap.