Following are a list of possibly useful resources:

• HowStuffWorks.com has a section dedicated to electronics. There is a sub-section for the learning the basics, which is useful for quick primers on concepts. Also, there's a page on amps, watts, volts and ohms which breaks things down well for the layperson.
• Here's a page on "converting" amps and volts to watts. The author links to another site which has an excellent explanation of Amps, Volts, Watts and Ohms from a mathematical standpoint.
• Electrical & Electronics, Ohm's Law, Formulas & Equations
• Electrical & Electronics, Ohm's Law, Formulas & Equations (and calculators)