Non-linear Interpolation

I have some coordinates:

X-127
Y-345
Z-2

Then a second later, I have some new coordinates

X-132
Y-328
Z-1

Now, I need to come up with some sort of math aligorithm to generate a smooth curve in between these two numbers, resulting in smoother movement.

To make a smooth movement you probably should only devide this one move into moresteps. to caculate the steps just use for each dimension.
(newvalue-oldvalue)/numberofsteps

From the data given I see now reason for a nonlinear Interpolation, only if your complete movement is nonlinear, but than you would know the nonlinear-function (wouldn't you).