replacing rotted wood on window?

I have an old window frame , with a rotten section at the bottem. what type or types of wood are good to use in replacing old window frames.
william, February 2006
I have the same problem with my shop display window, I am planning to remove the rotten wood, and replace it with pine coated in yacht varnish and white gloss to match the rest of the window.

Preseli Computing, February 2006