Just to add to Richard's answer, http://spanish.stackexchange.com/a/430/3051 (can't comment, i'm new):
In Spanish, there are times when both ser and estar can be used to refer to locations (preference might depend on local variations), and some times ser will be used always/most of the time.
For example, when talking about an address, you'll often see "¿Dónde es [esta dirección]?" or "¿Donde queda?".
When referring to something that will happen, like a party, using ser (in present or future tense) is the usual. For example:
"La fiesta es en mi casa." / "La fiesta será en mi casa." = "The party will be at my place."
"¿Dónde es el evento?" = ¿Where is the event (taking place)?
About the difference between the two verbs, is as stated in the other answers, but like a comment (by hipietrail) implies, evolution of the languages render this a very arbitrary distinction.
For some detailed information: