This past summer (Summer 2014), Elena Polozova and Bijan Mazaheri developed a nice quantum circuit simulator in Mathematica.

This simulator allows one to enter the circuit in text input (as a list of characters), with each row a qubit and each column a quantum logic gate (including Hadamard, phase gates, and CNOT).  A quantum circuit is produced along with the matrix representation of each step in the circuit.  We have simulated the Quantum Fourier Transform and Grover Search; Shor’s Algorithm is to come!  Download here

This Mathematica notebook was based on a Wolfram Demonstration by Alexander Prokopenya