As for your converter, I think they're called a 12V DC to 110V AC inverter. Your local Wal-mart should have one, watch the amperage/wattage rating on the one you get. They're not as cheap as you'd expect and definately not very efficient (around 50%) so it's gonna throw off heat. If you have a specific item in mind that you want to plug in, you might want to look at finding or building a power supply for it that will take 12VDC input. Most electronics runs on DC anyway, they just convert the AC running in your house to DC. So if you were running a laptop in your truck, for example, you'd be converting 12V DC to 110V AC, then back to 12, 5 and 3.3V DC.