The oracle is a monument made upon the rock that are four heads who knows everything in Albion, since their creation. This monument is located at Snowspire Village, in the Northern Wastes. If you complete the gold quest "The Oracle of Snowspire", you'll get all the four expression to talk to them.
They will talk about four things:
People of Albion History of Albion Creatures of Albion Places of Albion In reality, only the top head speaks.
One funny thing about the oracle is that the 4 expressions that you need to talk to them are YMCA, showing that the Lionhead Studios know how to make jokes.