I found another reference for Ser vs. Estar:
To quote that page:
"En (and in a few cases, a,) is most often used to describe a location or condition, and the linker is usually estar. The exception comes when the subject is an event rather than a person or object.
# Madrid está en España. Josefina está en la cocina. Mi sobrino está en segundo grado de primaria. (El lobo está a la puerta)
But: La clase es en Parlin. La fiesta es a las nueve. (These are events, not physical objects. In this case, ser can be translated as "to happen.")
Again, it doesn't matter if the location is changeable. Even though cities, buildings, etc. don't move, you still use estar to describe their location. They are located there; they don't happen there."
The rule I learned is that :
SER is used when talking about time (¿qué hora es?), destinguishing characteristics (él es alto), and the location of events (parties, concerts, classes, etc., as opposed to the location of people or things -- ¿dónde es la fiesta?), whereas
ESTAR is used for the location of concrete objects (Paula está en la clase) and for changing states , charactersistics, and conditions (whether the change is brief or long-lasting) -- estoy aburrido; Lincoln está muerto. Lincoln is dead means his state has changed but being dead does not define who he is as a person. The word "estado" (state) comes from "estar". The "estaciones" of the year (seasons) also come from the verb "estar" and indicate the changing states that the climate goes through.
ESTAR is related to the idea of "standing" as in "I stand corrected" or "I stand here in the state of being bored" (estoy aburrido) whereas ES has to do with the idea of being who or what you essentially are (I am a boring person = soy aburrido).
Another way to say this is that ESTAR (está) has to do with the STATE something (or someone) finds itself in, whereas SER (es) has to do with defining or essential TRAITS. For example, the sun is (es) hot (heat is an essential trait of the sun but the climate may be (está) either hot or cold, a changing state.