My iphone 3g will not recognize my sim card...it says no service... my iphone is unlocked..my sim card works on other phones..

Yes, provided the iPhone 3G is not locked with any other different network. If it is then, you need to unlock the iPhone.To unlock an iPhone the remote unlock service would be a better option because, you need not give your mobile to someone else nor do you have any chance to enter the wrong unlock codes. To get such an unlocking service for your iPhone 3G approach Wickedunlock.com and by submitting the country and network to which the mobile is locked to you will be able to remove the restriction from the respective network. This will be a permanent unlocking solution. Once unlocked you can swap networks.The iPhone 3G supports Mini sim...and hence insert the respective sim size.

HI if the iphone 3g 8gb is locked to some other network provider then it wont accept your network sim until you unlock it .You can easily unlock your iphone 3g with the help of providers like TheUnlockArena.com here they are rendering remote unlocking service to unlock all model iphone from network lock .....You first verify that whether they are rendering service for your country and network provider .If yes then pay for it and unlock your iphone..

For iphone, you can use remote unlock service to unlock it.You can get the remote unlock service from the site Simpleunlocking.com . Here,you need to provide the country,network provider name and IMEI number of your Phone.Then visit the site Mobileunlockguide.com . Here,they provide the free unlock instructions for your phone.After unlocking it,you can use different GSM sim card on your phone.

Yes!! Of course you can, provided, your iPhone is unlocked from its Network. If not, you need to unlock your iPhone, in order to use other Networks. You can unlock your iPhone 3G by Remote unlocking. The unlock is permanent and you can get this unlocking service from online sites.Try Superunlockcodes.com , they provide good unlocking service at reasonable price.

sure you can unlock it try remote Unlock service....

It not recognize Sim Card means ,it locked to Network,Get the remote Unlock service at here
http://www.prounlocking.com/supported-phones/rs8wp7/ and Unlock it from Network Lock.

I think it may not Unlocked 100% what Method You used for Unlocking,You can get the Unlock code at reliable cost at here
http://www.theunlockarena.com/apple-iphone-3g/rs13wp9/ and Unlock it,use any GSM Sim card,.

If the sim card, is an at&t card then contact a at&t store close to you and have them check the card.

If the sim is not a at&t card, the phone has to be unlocked so it can use other carriers.

If this is the case ,post back and ask how to get your phone unlocked.

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.

this is what you do

1. get a unlock card Click Here
2. get a Verizon Sim card click here
3. Switch off 3G network: Setting---General---Network---Enable 3G---Off
4. Turn off the iPhone 3G, take out the SIM tray, place the Unlock Card and the SIM card on the SIM tray, put back the SIM tray into the iPhone
5. Turn on the iPhone
   There is NO NEED TO CUT YOUR SIM!
   
   
6. Just Plug & Play!