I have installed a new 200amp load center outside by my electric meter. Inside the load center the electric inspector told me that I needed 2 100amps to run to 2 separate moblie homes, so I did that. Now I am ready to run the wires they told me that I needed 3 wires and 1 ground wire, so I did that. Now inside the load center I have 100 amps circuit breakers and I need to know where to run the ground and netruel wires

Ahh, first off are you sure you can do this yourself? It seems if you don't already know maybe you should hire a qualified electrician. Look I do a lot myself but I know when to call in the big guns. Anyway...

That being said you run the neutral and ground wires to the bars that you grounded when you installed the 200 amp main service entrance box. NEC requires you ground the main service entrance in two places if possible; to a grounding pole in the earth and to the homes plumbing system (where it enters the house) if made of metal. There are exceptions to this rule and some things I left out, that one of the experts on this site can tell you I am sure.

When you wire the sub panels for the mobile homes you will hook up the two hot wires to the 100 amp breaker in the sub panel – which will feed the hot bus bars. The neutral to one of the other bars (should be sliver) and the grounding wire to a green bar. Only at the main service entrance can the neutral and grounding wires come together.

I am no expert but I think the above is all correct, but again are you sure you really want to do this yourself? I would at least see how much a professional would cost.