Links

Atmel:
http://www.atmel.com/

Arduino:
http://www.arduino.cc/

Arduino Forum:
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl

Moodle:
http://moodle.op.ac.nz/course/view.php?id=1301

MindKits:
http://www.mindkits.co.nz/

photocells:
http://www.ladyada.net/learn/sensors/cds.html

Basically gives you a bunch of info about the LDR and some small examples of using one.