IQ scores (and the tests) were not created equally, and they have not been calibrated internationally. From my understanding (as a psychology student), IQ tests from the USA give roughly a ten point advantage over tests from other parts of the world. This isn't saying that people from the USA are either "smarter" or "more stupid", just that the tests are scaled differently. The relationship is apparently (and understandably) linear, which makes it easy to convert, yet still mildly confusing.
As many have said, IQ tests do no measure a person's intelligence. Rather, they measure a section of a person's intelligence. They have their place as a quick, easy and cost-efficient way to get an indication of how different people react to the same circumstances/problems/questions.
However, it is all too easy to take them out of context and either overrate or underrate them. I've always thought they should be renamed to imply less of an absolute measure. Unfortunately, my IQ score of twelve severely inhibits my ability to think up a good name.