walter said:
>   Last time I checked there weren't any
>   available through Gutenberg at the
>   pretty basic level they are needed.

open-source textbooks are an idea whose time has come.
there are now various entities gearing up to pursue them.
i'd suggest that you take a good look around cyberspace.
even if they aren't here yet -- and i don't think they are --
they will be soon, perhaps very soon.  best of luck to you!

-bowerbird