Iphone i just received phones yesterday and the phones will not work with sim card but it's unlock, but saying no signal

If you have problem in accessing with any specific SIM card in your iPhone, You can make a complaint to your network provider and get a new one.
If you are not able to access any SIM card in your iPhone, Take your iPhone to a local mobile store.
If you are not able to access any SIM card other than a specific SIM card in your iPhone, then your iPhone must be network restricted. You need to unlock it.
The safest and easiest way to unlock an iPhone is to unlock through remote unlocking method. You can get the remote unlocking for an iPhone from www.wickedunlock.com/apple/rs11wp8/ at affordable cost. This method of unlocking doesn't require a Jailbreaking too.
Here are the steps to unlock an iPhone,
1. Wait for us to send you an email saying your phone has been activated or remotely unlocked.
2. Install the latest version of iTunes.
3. Make sure your Apple iPhone phone software is updated to the latest version using the iTunes software.
4. Connect your Apple iPhone to iTunes with a NOT ACCEPTED SIM card.
5. Wait until iTunes detects your Apple iPhone.
6. Disconnect your Apple iPhone and reconnect it after 10 seconds.
7. Your Apple iPhone is now unlocked.

No Sim Card Installed Insert a valid Sim with no pin lock

Hi sounds like you have updated and undone the unlock you will have to get it unlocked again iam afraid.
regards

Reset the iPhone:
It has been observed that simply resetting the iPhone can resolve signal strength issues.
Reset network settings:
In some cases resetting the network settings has also helped so tap Settings, tap General, tap Reset, tap Reset Network Settings.
This will restart your iPhone and will also delete any stored Wi-Fi passwords as well as DNS settings and more.

Place your SIM card again:
If your iPhone’s SIM card is not placed properly, it has been observed that it can affect signal strength.
So a good idea would be to remove your iPhone's SIM card by pushing a straightened paper clip into the small hole on the top of the device to open the SIM tray, then check for debris inside the tray or SIM card slot, remove it by blowing into the slot or using compressed air and then placing the SIM card properly and then re-inserting the SIM tray.
The notion is that improper SIM contact can result in a weak signal, so the above procedure could help.
Attaching scotch tape to the SIM card:
This is indeed the most ingenious methods, it appears that attaching a small piece of scotch tape to the outer side of the iPhone’s SIM card (the side of the SIM card that does not have metal contacts) can result in a surprising boost again borrowing from the notion that improper SIM contact can result in a weak signal.

Well, your SIM card must be compatible to your iphone carrier. From what I understand, so far only AT&T is able to give out SIMs for iPhones; however, that may have changed to the addition of another carrier (perhaps Verizon, or so I hear) If you have the correct SIM card, then I would suggest that you go to your nearest wireless store and ask for one that may help your situation. Otherwise, if you don't want to do that then just unlock your phone :) There are videos on youtube that you can look at, programs that you have to download and what not, but it's doable.... or you can take it to a side stand wireless and have them unlock it for you :)

http://www.crunchgear.com/2009/01/01/how-to-unlock-your-3g-iphone/

have a look at the above site.Your problem i think is the phones not been unlocked to accept other sims.

Hope i`ve helped.

the new sim card is connected with having an iphone account. when you say it is officially unlocked.
does this mean that AT&T unlocked your phone?
what i think your saying is that if you have 2 sim cards, one that is in use and the other is a spare you cannot use both. at the same time.
the sims are standalone, to use a spare sim it has to be activated by the carrier, thus disabling your original sim.
when you change sims you will need to reboot the phone that will not change.

I recommend you restore your iPhone, if you don't know how, i'll be happy to walk you through it. After that, upgrade to the new firmware. After you have upgraded, unlock it with the newest PWNing software. That should fix your problwm.

Find your solution from the list,
Apple Iphone Smartphone
Codes:

• Unlock Code,
• Password,
• Puk Code,
• Lock Code,
• Other Codes.

Software & Hardware Problems

• Software Problems (Hang, Youtube etc.)
• Hardware Problems (Display, Charging etc.)

Find Your Solutions for Apple Products:
Apple Iphone 3G
Apple iPod Touch Digital Media Player

i put the sim card into iphone is dont work