The current Federal Tax Credits are included in the link below. Your electric service provider could also offer credits..ours is giving us $750.00 a ton rebate for going geothermal and also a $500.00 credit for insulation.

Here is a link that might be useful: Federal Credits

There is also a $2000 tax credit for energy star builders if the home tests out at a % below current energy star 3.0. While this is a credit for the builder (I get it since I build my own home) it may be worth asking about and possibly working it into the bid number. However I think they expire in 2015.

Along the lines of the rebates from local suppliers, my gas supplier gives a $2600 for ES3.0 home and electric gives about 1050 plus appliance rebates so be sure to check into that.
Also, it pays to do your research on your options and combinations. For example, depending on your climate and ICF brand, geothermal may not be worth the cost compared to traditional HE gas furnace depending on your gas and electric rates. For my ICF home, geo had about a 30 year payback even factoring in the tax credit (you still need to front the money and then wait around for the credit mind you!). The better and tighter you build your shell, the smaller your hvac needs to be. My 3800sqft home in zone 6 only has a 2 ton furnace in it. It is -6 outside right now and furnace only runs about once an hour.
Put your money in your shell first, then look at hvac options. Geo isn't always cheaper.