I had a iphone 3gs and now have a new iphone 4. I can't remember my passcode from my old phone. . I afraid to push the passcode on and get locked out. what do I do.

If you didn't remember your passcode to get into iPhone, you have to reset the passcode. There are a few ways to reach this aim. Check below steps to do that.

If you haven't synced your iPhone with iTunes before or if you haven't enabled your Find My iPhone on, you can take advantage of the third method. Resetting iPhone Password in Recovery Mode is not complicated. The steps below will show you how to do that.
Step 1. Disconnect all cables from your iPhone and turn it off.
Step 2. Press and hold the Home button and connect your device to iTunes. If your iPhone does not turn on, please turn it on manually.
Step 3. Continue holding the Home button until you see the Connect to iTunes screen. iTunes will remind you that it has detected your iPhone in recovery mode.

Step 4. Click OK. The Summary tab in iTunes appears. Click "Restore iPhone" and restore your iPhone.

Recovery Mode will erase all your data and passcode from your iPhone, resetting it to factory defaults. Thus, you'll have brand new iPhone without any personal data after you reset iPhone password with Recovery Mode. Therefore, please consider carefully whether you need to use this method to reset password on iPhone.
If you remember your current iPhone password and you just want to change into a new password, you can finish it with ease. Go to Setting > General > Touch ID > Passcode (iOS 9/8/7) or Passcode Lock (iOS 6), then enter the current password and tap Change Passcode. Then enter the new passcode. Now, you have reset your iPhone password.

For more methods, check: How to Reset Password on iPhone

You can if it is a simple password- only four numeric digits. If the complex pass code was enabled in your settings then you will have to restore it through iTunes and lose all of your saved info. If you aren't worried about that just turn the phone off, hold the home button down while you plug it into your computer and keep holding the home button down until iTunes recognizes your phone in recovery mode. Then follow the prompts on your screen until it is restored. If you are trying to save the info on your phone just go to iPasswordhelp com and follow the instructions. I'll link the video below.

find a repair center to flash it

mmmm write on the youtube that problem

You can unlock your iphone 3GS using Remote unlocking method.It's the best and secure way to unlock iphone.If you are interested in this method visit Classicunlocking.com Here you can unlock your iphone without jailbreaking.

The only way to open it if you can not remember the password is to restore the phone to factory default settings via iTunes.

you will have to restore it. The only was is deleting everything hopefully you have a backup on itunes.

Hold the power and home key once the phone phone turns on then release the power continue to hold the home key. make sure you are plugged into itunes and when it ask you to restore then click yes. If you are unlocked to tmobile this will undo the unlock also. Precaution if you are running on 3g updating to the new firmware will run laggy also. if you on 3gs or iphone 4 you dont have to worry about it running laggy. hope this helps

i have apple iphone model no.A1303 FCC ID BCGA1303B purchase in USA but in India local network is not respondingplease give me solution

hmmmm...

you need the latwst version of iTunes
USB iPhone cable
and internet connection.

just restore your iPhone in thesame version. problem solve but all the files in your iPhone will de earased.

Bad News... you may have to Restore from iTunes. Here is some info from the users manual:
Passcode Lock By default, iPhone doesn’t require you to enter a passcode to unlock it. Set a passcode: Choose General > Passcode Lock and enter a 4-digit passcode, then enter the passcode again to verify it. iPhone then requires you to enter the passcode to unlock it or to display the passcode lock settings.
Turn passcode lock off: Choose General > Passcode Lock, enter your passcode, and tap Turn Passcode Off, then enter your passcode again. Change the passcode: Choose General > Passcode Lock, enter your passcode, and tap Change Passcode. Enter your passcode again, then enter and reenter your new passcode.
If you forget your passcode, you must restore the iPhone software. See “Updating and Restoring iPhone Software” on page 204.
Set how long before your passcode is required: Choose General > Passcode Lock and enter your passcode. Tap Require Passcode, then select how long iPhone can be idle before you need to enter a passcode to unlock it.