This seems to be the question du jour. If the data is actually on a grid, you should just be able to reshape your vectors into matrices. If not:
% Make some fake vector data
x = rand(100,1)*4-2;
y = rand(100,1)*4-2;
z = x.*exp(-x.^2-y.^2);
% Put data onto a grid
[qx,qy] = meshgrid(linspace(min(x),max(x)),linspace(min(y),max(y)));
F = TriScatteredInterp(x,y,z);
qz = F(qx,qy);
Either way, once in matrix form
surf(qx,qy,qz)
