Article
Other

Controlling the Real World With Computers: Boolean Logic

For Students 9th - 10th
This site contains an indepth discussion of boolean logic and includes bit-wise operations and manipulation.
Article
Khan Academy

Khan Academy: Logic Gates

For Students 9th - 10th
The Not Gate or the inverter is explained as is Boolean Logic.
Article
Khan Academy

Khan Academy: Review: Logic and if Statements

For Students 9th - 10th
A review of logic and "if" statements, if/else statements, and conditional expressions