A good way to learn is this:
1. Read up on the basics of assembler (from e.g.
http://webster.cs.ucr.edu/AoA/)
2. Get yourself a copy of IDA Pro (a demo is fine too -
http://www.datarescue.com/idabase/idadowndemo.htm)
3. Compile some simple programs and examine them in IDA
Single stepping through your program using the Visual Studio disassembly window is also useful.
You'll soon get a good idea of how it all fits together.