I've just uploaded the latest version of my Sudoku Solver.
I wrote the initial version of this in March 2006, and have since been in competition with Dimitre Novatchev to have the fastest solution. Dimitre's held that title for while, but with this version I think I may have won it back.
The additions here are Naked Tuple discovery in the first phase, and then repeatedly re-ordering the cells by least-number-of-possible-values as each cell is populated in the second phase. Sounds obvious but its something I missed first time around.
On my machine this latest version solves the vast majority of puzzles (including AI Escargot) in under a second, with the occasional one taking just under two seconds. The previous version would take up to a minute on some puzzles, so I'm pleased with improvement.
Hopefully Dimitre will do some comparisons using his latest version, and then tell me the good news :)