A good introduction, but a couple simplifiers:

1) You can read a photocell directly from a PC without an Arduino. The PC serial port and a couple of passive components can be used as a simple analog-to-digital converter for a cost of pennies. One of many examples can be found here: http://www.cedarlakeinstruments.com/blog/archives/10

2) Similar idea using a Beaglebone or Raspberry Pi would eliminate the Mac/PC for a more compact solution.

I always like seeing how other people connect their arduino to the internet. I did something similar using python to read the data and then post it to Thingspeak. (my blog post: http://smallsciencebigadventures.com/arduino-temp-sensor.htm...)

Seems nice but something is weird with the layout of the article: http://i.imgur.com/qKi4JNR.png

undefined