I think Steve's view on Intelligence in his book is one of the best places to start, actually.
And since I don't have the book here, the way it stuck in my brain was:
Truth and awareness are major components in intelligence. Not looking at brain-specs, but the ability to see and connect truth, that's where the ability to learn is, and thus the real brain power.
And that gives you all you need to know! Be open, be aware, ask why, be like a child!
Personally I think IQ tests are fun, and a great way to play and learn at the same time. However, in my opinion they are very limited ways of looking at intelligence.
Intelligence is such a great thing. It's available in unlimited supply, and all you have to do to get more of it, is to be open. Let go, and let your perspective be changed. For me personally, reaching a new insight (helped by people like Steve) on a subject, is one of the most exciting things in life. All around me, people act like the world is what it is, and they have all the (wrong) answers... to figure out something new (and not meaning new, as in, nobody has ever thought of it, but more, more to me), man it's awesome.
Like the other day, when I realised that justice is an action, not a reaction... Such things take my breath away(but that's a whole different topic
)!