Victor Reyes wrote:
> Did anyone know of a Sudoku algorithm, which I can use to implement a Ruby
> solution?

You might want to have a look at Ruby Quiz #43 (Sudoku Solver): 
http://www.rubyquiz.com/quiz43.html

Alternatively you could also solve it using constraint programming with 
Gecode/R: http://gecoder.rubyforge.org/examples/sudoku.html

-- 
Andreas Launila