I hope it can  read in a transistor model, then help you calculate  and make the conversion between  the w/l, Vgs-Vth, Ids , Gm and so on.  You know the hand calculation is difficult especially for Bsim3v3 model. So such a software will help me a lot on analog designing.      

I have found a such procedure base on HSPICE . I feel it is useful and paste the link here, http://homes.esat.kuleuven.be/~tchen/JMOSCal/.  Bacause the procedure is tentative,so any suggestion will do good to it.