Yasminoku is a sudoku game, generator and solver created by Joan Alba Maldonado on 25th of July 2006 which has been now improved.
HoDoKu is a sudoku helper written in Java and available in English and German. Generate sudokus in five different and fully configurable difficulty levels. Solve them yourself (with help from HoDoKu's hint system) or let HoDoKu do it for you.Discontinued
The project seems to be no longer updated, but last version, 2.2.0, released in July 2012, it's fully working and can be still downloaded from the official website.
Griddition is a math puzzle game in which you must test your addition skills across over 190 levels of increasing difficulty and enjoyment, earning trophies and bragging rights along the way. Think of Griddition as Sudoku for the 21st century.