Yeah it's the fuse panel on the drivers side, there is a door covering it. That is actually where I installed the switches that I use for my exterior and interior neons. I just drilled through it, that way if I ever want to get rid of it all, I just need to get a new fuse panel door, very cheap.
You are right about how to splice them together, just join up all the postive ones from the LEDS and attach them accordingly, same as the negative ones. I would leave the cigarette lighter along and just run some new ground and postive wires..... you never know if you might need the cigarette lighter to charge a cell phone or whatever......
Also, when you wire up anything, DISCONNECT THE BATTERY. Best advice I can give you, it's less painful, especially when wiring up a transformer for the undercar neons (PM me if you want to know what happenned....lol).....