Relay question

Ok, this is a hard question to ask. I dont know all the terminology so bare with me. I want to make some lights come on in my car like DRL when the car is on, or when the key is switched to accessory power. Thats what the switched wire is up there. It is for example the power antenna wire. Once the car comes on I need a relay to make contact and complete the circut. I also need it to handle no less then 15amps. So were looking at a 12v, 15amp relay. Im not sure what 3 or 4 pole relays are.

Could anyone out there give me a relay to buy? Like a model number I can just go to radioshack and pick up? Or if you could give me a link ill buy it online. I just really need to know what part I need without wasting tons of time trying ones out that dont work.

Thanks, Nate

daaang that was a fast reply!!!

thanks alot man