How to enable a disabled iPhone: Apple Support Communities‎

If you enter the wrong passcode six or more times, you'll see a message that says one of the following:

iPhone is disabled
iPad is disabled
iPod touch is disabled
The message says to try again later:
[You must be registered and logged in to see this image.]
After too many attempts, your device may display, "[Device] is disabled, connect to iTunes".
[You must be registered and logged in to see this image.]

If you have previously synced your device with iTunes :

You may be able to reset the passcode by restoring the device.

Connect the device to the computer with which you normally sync and open iTunes.
Note: If iTunes prompts you to enter the passcode, try another computer that you have synced with. Otherwise, go to "If you have never synced your device with iTunes", below.
Right-click the device in the left column and select Back up.
When the backup is complete, select Restore.
When finished, restore from your most recent backup.


If you have never synced your device with iTunes

Connecting the device may result in this error message: "iTunes could not connect to the [device] because it is locked with a passcode. You must enter your passcode on the [device] before it can be used with iTunes."[You must be registered and logged in to see this image.]

Disconnect the USB cable from the device, but leave the other end of the cable connected to your computer's USB port.
Turn off the device: Press and hold the Sleep/Wake button for a few seconds until the red slider appears, then slide the slider. Wait for the device to turn off.
While pressing and holding the Home button, reconnect the USB cable to the device. The device should turn on.
Continue holding the Home button until you see the "Connect to iTunes" screen. When this screen appears, release the Home button.
iTunes should alert you that it has detected a device in recovery mode. Click OK, and then click Restore to restore the device.


If you don't have access to a computer

If you are using Find My iPhone, you can use Remote Wipe to restore your device. If you have been using iCloud to back up, you may be able to restore the most recent backup to reset the passcode.