For the past couple of days I have been working on this. It is a Sudoku solver and generator. It is able to generate Sudoku puzzles with unique solutions and solve any Sudoku given to it (which has a solution, of course). Also, you're able to save/load any game you are playing. I will go into more detail about the algorithms I wrote for this in a later post. Here is a screenshot of the "Sudoku Machine" in Windows
As you can see, I was going for a very minimalistic appearance
Here are some links to downloads for the Windows and Mac versions of the program which both include the source
Windows:
https://dl.dropbox.com/u/20642158/sudoku_windows.zip
Mac:
https://dl.dropbox.com/u/20642158/sudoku_mac.zip
Imout!