How to solve a KAKURO Puzzle?

How to play Kakuro The rules of Kakuro are simple - place the numbers 1 to 9 into the puzzle grid so that each continuous horizontal or vertical run of empty squares adds up to the value to the left of it or above it respectively. This value is shown either to the right or below a diagonal line. There is one other key rule: the same number cannot be repeated within any run, so the solution to the value '4' cannot be 2+2 but must 1+3 (or 3+1).