MY WESTEROS LINKS (RECOMMENDED)

Westeros Wiki (a Wiki of Ice and Fire): http://awoiaf.westeros.org/index.php/Main_Page
In Spanish: http://hieloyfuego.wikia.com/wiki/Portada
French: http://www.lagardedenuit.com/wiki/index.php?title=Accueil 
Italian: http://wiki.labarriera.net/index.php/Pagina_principale
German: http://de.eisundfeuer.wikia.com/wiki/Das_Wiki_von_Eis_und_Feuer

I've also made family trees in a notebook (Oberyn needed, at length, one for himself for all his loves and offspring, aside from a crest with sunglasses on the Dornish sun and a Kalashnikov instead of a spear):

Exactly what it says.

The wikis are great for checking, for instance, place names and events across translations.

TRIVIA

Did you know, for instance, that the surname of the most powerful clan in Westeros is spelled Lennister, with an E, in the German translation?