For the cup holders I used these. These were on another thread here but I can't find it right now. If I do manage to find it I will link you to it.

They come rigged with a resistor already inline so that they can be wired up to 12V DC (i.e. the main battery) without having to do anything special. I just T'd into the courtesy lights using these t-splice connectors that you can get at any auto parts or hardware store.

These particular LED's sit perfectly on top of the drain hole on my 2009 Outback V cup holders without having to actually fix them to anything. I just popped the wires down through the hole T'd them into the courtesy lights and was done.