Via this post on Nexen.net today, there's a pointer to a few Sudoku puzzle resources that use PHP for a variety of reasons.

They hhave four items listed:

• Sudoku in PHP
• a Freshmeat Sudoku project
• the source for a sudoku puzzle solver
• a Sudoku solver class from PHPClasses.org

Personally, I just enjoy working them - the solvers take the fun out of them. I can, however, see where they might come in handy if you don't have the answers where you can get at them...