This page might help. I did a search for HC12 addressing modes since that's what we learnt with, and it is MUCH better to learn on a simple processor rather than jumping into the deep end with something like an Intel processor. The basic concepts should be similar for any processor though.
http://spx.arizona.edu/ECE372/Supporting%20Documents/lecture/HCS12%20Addressing%20Modes%20and%20Subroutines.pdf
I wouldn't imagine you'd need to know any of the more complicated ones in an introductory course. We only really used the basic ones, then had to explain a few of the others in our exam.
You should be able to see what's going on on a physical level from that provided you understand the assembly code examples. The inherent addressing command inca for example is going to use a set of logic gates within the processor (http://en.wikipedia.org/wiki/Adder_%28electronics%29) in order to increment register A by one. That's all well and good but trying to understand the physical layer of anything more complicated than that is just going to give you headaches. You really don't need to know it, which is the whole point of using a microprocessor in the first place.