On a more theoretical note there is some people are writing other, more robust and generic simulators of a quantum computer. The following web sites have information about quantum computing, and have code for simulating the action of a quantum computer. I found these sites to be great resources during my study of quantum computing.
Note: This section has not been updated since 1999.
http://tph.tuwien.ac.at/ oemer/qc/qcl/qcl.html
http://tph.tuwien.ac.at/ oemer/prakt/prakt.html
http://www.openqubit.org/