[Edu-sig] learning algorithms

[roberto]

I have to help a teenager who's fond of computer science.
He told me he wants to learn "the tough algorithms out there". Of
course, nobody helps him at school.

I'd like to know some resources to guide him from the very basics of
programming to as far as he can at the moment.
Since python is my first choice, personally speaking, can you give me
some suggestion about a step-by-step introduction to algorithms ?

Thank you !

-- 
roberto