I have led to install under the dash in the footwells but I want them to come on when my car door is open. I was thinking about hooking them up to the dome light but i dont know which wire to run the power wire too?

I also want them to turn on by a push of a button. Can anyone help me with this?

 

you'd need a SPDT Switch to control what 'mode' your lights (Cathode or LED) would be in. 1 mode would be off, another would be "door" and the last mode would be "always on" (similar to the function of your dome light)
You can pick up the switch you need over at oznium.com if you're looking for an OEM look, or you can find them at almost any electronics store. (ie: radio shack)

Check the electrical diagrams for the wiring information you'll need. They are in a sticky at the top of this forum.

 

You'll most likely need a relay for the use of a switch as well as a door trigger. Don't use the door switch as a ground, since it will only work when the doors are open and key is in. Install them with a switch and then put in a relay. There are about 20 DIYs around the forums.