Seriously check this link out! Just enter your server and it tells you which ore is selling for more than usual and which is selling for less than usual. This is good for two things:
If you play the AH like me and buy anything ore included that is below a certain price, this is a good way of quickly seeing which ore you should put up for sale today.
If you have mining you can quickly see what to mine to make the most gold!
Its just such a great website I thought more people should know about it!