I think I've found the best Sudoku application available for free. OpenSudoku sets a whole new standard in free, fluid, clean, and ad free software. It's not too full of bells and whistles but if you're like me, you play the game to keep your mind active. It comes with over 100 puzzles and you can download an additional 1200 from their website.
http://code.google.com/p/opensudoku-...d/wiki/Puzzles