Forgot my passcode

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.