Where are all those constants?

Where can I find a single-source summary of all the registers for low-level programming?

In the pwm tutorial there are bitwise operation on ports such as OCR1A, OCR1B and TCCR1A. Where can I find references to these. I have the datasheet but its +400 pages long.

There are various header files that define (and sometimes explain) the values. There are a number of boards that are supported, so, there are a number of header files.

If that's not sufficient, there is always the data sheet. Or a search of the forum for the specific value you are interested in.

sort of related question. Is there a way to get a compiler or assembler listing that would show those header files and there resolution?