Surfulator looks cool, but $59.00 !  I usually use del.icio.us to store links and pages, but it doesn't show the detail that Surfulator appears to

It looks like your typical sudoku game - nice graphics - follows the KISS (keep it simple) method of design.

I would add (unless I missed the feature) a way to (whats it called?) "mark" the numbers I think it might be like...
+----+
! 123 !
! 456 !
! 789 !
+----+
only obviously not all numbers would be there, only the ones that I think might not be used in column / rows

Good job, though