My friend, Fizzylizzy, added a great link to Websudoku which is an online sudoku game. I love the How am I doing help button and have to restrain myself from hitting it after each move. But -- dagnabit! -- the Safari browser quit as I was nearing the end of the puzzle!! Our laptop is about done when it comes to memory space and it has been shutting things down more and more frequently. Makes for a tense and exciting game!
(Think faster! Faster!!)