This is a continuation of the now-read only thread from the old forum:
http://arduino.cc/forum/index.php/topic,22670.0.html
To answer the last poster's question about Ethernet shields, I use an ENC28J60 based shield from Nu Electronics (www.nuelectronics.com). This can be picked up from them, or on eBay, for 1/2 the cost of the official ethernet shield. I think if I were to do it again, I would get the official one, as I spent 3 weeks hacking together the poorly documented example code to get something usable for me. It doesnt use the same library as the official shield.
As for what I use it for: I use it to log data from my tracker to a MySQL database, via PHP scripts. This lets me log data very easily, and once you have it pushing to a database, you can do anything you want with it. My demo (as I am learning PHP and MySQL very recently) is at http://solar.panicdog.com
The trouble I am up against is the Ethernet shield and the AdaFruit motor shield I am using, are running on conflicting pins. I will start another thread to discuss this, as to not derail this topic. If I cannot resolve the conflict I may have to run the two shields on different ATMega328's, and have them talk on the I2C bus (which I'll be using in this project anyway, so not a problem I suppose).