Sudoku Hint Free is a free application (No Ad-ware or internet connection of any kind):
It has these features:
- Provides hints for solving Sudoku puzzles, including number hints and color hints
- Allows entry in multiple colors for following various solution paths
- Allows a user to enter puzzles from other sources
- Generates new random games with 4 levels of difficulty
- Solves **any** solvable puzzle in a fraction of a second using the most advanced "dancing links" algorithm
- Provides built-in help and 10 sample games

The Free version only allows one puzzle at a time.
The Plus version:
- Allows the user to name puzzles and store and retrieve them
- Adds a Cheat option to the menu for revealing a single cell of the solution
- Adds a Validate option to the menu for checking to see if the entries made so far match the solution