Well, for Java they have MegaMek . . . they do not have to worry about the rules, just move the mechs and fire. But I think you want them moving minis on maps so . . .
They have built a mech campaign tracker in Java- works with MegaMek (MM) IIRC, you can see it down on the computer game sub-forum.
I know my wife found a dice aid/app for her phone when she tried to kill me at the local con a few years ago. She put in her mech, her movement, and a couple of other inputs and it told her what her THN were for each weapon on the mech.