Killer solver is a powerful but simple app designed to help solve killer sudoku puzzles.
You just enter the target total for the cage, the number of digits in the cage and then select any numbers that you know must be included in or excluded from the answer.
Killer Sudoku Solver
The possible combinations of numbers are then displayed in a list
Any combinations that you know will not work can then be greyed out by pressing the green button next to the combination.