HoDoKu is a Sudoku generator/solver/analyzer. It has many human-style techniques (singles, subsets, LCs, fish, wings, uniqueness, coloring, chains, and ALS) and a powerful analyzer (manage multiple solutions for one Sudoku).
Sudokuki is a graphical SUDOKU game. It solves even the most difficult sudoku grids for you. It can generate a sudoku, play sudoku, and print a sudoku.