Web-resources for learning how to read electrical circuits
There is more to schematics than just being able to "read" them.

To read them you may think you just need to understand what the symbols mean.  Yes, that is an important part of it, like knowing what the letters of the English language mean.  But you also need to understand how the components in the circuit work, and how they interrelate to each other (kind of like Grammar and Syntax).

To learn the symbols all you need is a list, like this one: http://www.kpsec.freeuk.com/symbol.htm

However, to understand what the components do and how they work you will need the following:


Knowledge and training of the basics - resistors, capacitors, transistors, inductors, etc.
Knowledge and training of how the more complex devices operate and interrelate - op-amps, microcontrollers, other specialist chips.
Data sheets for any components that are more complex than a simple resistor or capacitor (unless you require high tolerances in which case you may want data sheets even for those).


So it's not like learning to read another language, like say Japanese.  It's learning the language and the culture and the history of the country.

Yes, there are often common themes in circuits, where you will see recurring schematic chunks - like the Darlington Pair, the Emitter Follower, etc, but even a common circuit chunk like that could operate completely differently in a different circuit.