A Level Maths Stats2 CourseworkWatch
I and other people in my class doing it have used: http://nationmaster.com
They'll do you for all the international type statistics (GDP, GNP, life expectancy etc).
If you plan on doing something related to exam results though, which seems to be a fairly standard topic (at least I've seen a lot of previous examples), you could ask teachers for the data perhaps.
In terms of things which have good correlation...
GDP -> Life expectancy
GDP -> KwH (per capita)
GCSE exam results -> AS/A2 exam results
Air pollution -> Cases of cancer
There's a whole host of things you could do, use your imagination.
Which units do you have to do coursework for? And is it optional?