If so, what's a useable algorithm to plt intrados and extrados?

http://en.wikipedia.org/wiki/NACA_ai...t_NACA_airfoil

dy_c/dx you can get by differentiating between two arbitrarily chosen
points on the camber line. You'll probably need closer spacing of
these points near the leading edge.

How do I calculate from the basic parameters the behaviour of the profile, i.e. the Cl curves?

What are you looking for? Slope will be very close to 2 pi ;-) The
angle of attack of zero lift is -2 f/t (f/t is maximum camber relative
to chord). The cm is more difficult to estimate -- it's easiest to
just plug the airfoil into XFOIL and do the calculation (or do you
prefer
http://www.iag.uni-stuttgart.de/IAG/...lettheorie.pdf
?). The rest, like clmax, are viscous effects and can't simply be
deducted/estimated from the basic parameters.

And perhaps other nice info like the leading edge diameter?

For NACA 4-digit-series, see the Wikipedia page.

Generally: any pointers to in-depth information that a non-engineer can mentally digest?

We would need more information on what you are actually looking for.
It could be structural properties of the airfoil (which XFOIL can
handle as well ;-).

Oliver