One of those quizzes helps you decide. Take it here. My result is below. The most interesting thing is, perhaps, the quiz authors' view that the Tories are pretty neutral on EU integration. I also have a big quarrel with the BNP has neutral on the right/left scale. I'd put them clearly on the left. (And for the avoidance of any doubt I shall be voting Conservative in June!).
1.45pm: I'm told there's this Vote Match too.