Can I get an explanation of Ohms, resistors, voltage, etc?

I want to get into circuitry and electronics, and I recently picked up a breadboard at Radioshack. I didn't get any other components because I don't need what types I will need. I know the function of resistors, but I'm pretty confused about V=IR. Is voltage the power of the power source used, i.e. a 9 volt battery? Also, what is the difference between the current and the circuit? And I'm confused because I see resistors with thousands of ohms while, in the equation, you usually don't deal with thousands of volts. I haven't been able to find a nice simple explanation. Also, keep in mind that I am just starting out in electronics and I only have a basic understanding of components.