Lambda the Ultimate

I received this Sudoku url from a friend. He says he's solved it up to here, but he's stuck:

http://www.freesudokuhost.com/showsudokuhosting.php?id=20051224213001997

I'm unable to move ahead either. I asked my friends, but no one is able to help.

I'm fairly good with Sudokus, and so is my friend who sent this to me. All I need is just the next step. I can (hopefully) solve it from there.

Thanks,

Elizabeth Daniel.