How to set up black Iphone 3 or 3g?

I got a black iPhone 3. I'm not sure which one it is but it's the third one. I turn it on and it takes me through the simple process. First language, then Region, then it makes me connect to Wi-Fi so I'll try that and then it says "It may take a few minutes to activate your iPhone" and in the end it says "Your iPhone could not be activated because the activation server is temporarily unavailable. Try connecting your iPhone to activate it, or try again in a couple of minutes.".So I'll try to connect to through itunes on my laptop and after a while it'll say "We're sorry. We were unable to continue with your activation at this time. Please try again later, or contact customer support." I tried costumer support but I don't know my serial number. Please help?

Added (1). I only have the phone, no box and I'm not sure what carrier. Nor do I have the equipment to open her up

Your serial number is located on the box. If you really mean you got the third iPhone, I'm assuming you have the iPhone 3GS.

When you are unable to activate, it means that you either do not have the SIM card in the phone or there are too many people activating at the time and you'll just have to wait for a later time.

For help, you could call Customer Support again OR you could visit your carriers store (AT&T, Verizon, Sprint, or T-Mobile) for direct activation or you could visit an Apple Store to help you with any problems you may have.