How to solve Tower of Hanoi iteratively?
You can transform the recursive solution to an iterative solution. To do this, create a stack that will contain items consisting of quadruples ("from", "to", "via", "num_disks"). For every function "call" in your recursive algorithm, push the parameters to a stack in the iterative algorithm. For every function "return" in your recursive algorithm, pop the parameters from the stack in the iterative algorithm.

Wikipedia has the complete iterative solution.