Pin Wiki is a great site, contains a lot of info now, although I rarely need to use it. I just did a quick search and did not find the reference info i wanted listed, in understanding how to read schematics you can study reference links like these. Schematics are basically your road map to what you are seeing on the PC board it's self. As LTG mentioned the IC chips are making the connections internally that you don't see.

http://en.wikipedia.org/wiki/Reference_designator

http://en.wikipedia.org/wiki/Electronic_symbol

Finally found it, it's section EM games, 4.1.1 Schematics.

http://tuukan.fliput.net/emkytkis_en.html

You'll find when you reference the schematics against the real boards you will see the schematics are written in multiple fashions. You soon see that tracing a simple circuit requires a few pages to be opened at the same time as you reference the types of "artwork" on the pages depicting the circuitry.

http://www.allaboutcircuits.com/vol_4/chpt_6/1.html

http://en.wikipedia.org/wiki/Circuit_diagram