One question to everybody

[Sonnet Nguyen <Sonnet.Nguyen@fuw.edu.pl>]

Hi friend,
I have a good friend who is socjologist and he has one question to you: 
Consider the following elementary problem (interpolation's problem):
Given n points in the Euclides space R^{3}. Find a smooth (minimal) 
surface containing these points.

Questions: 1) Is there a grafical program which can do that? (mathematica,
              plot, ...)
           2) If we want to find a polynomial of 2 variables
              which has a graph containing n points, then are
              expressions of polynomial's coefficients known?   

Please a quick answear.
SN

BTW. The similar 2-dimensional problems are Newtonian and
     Lagrangian.