One feature that is severely lacking on the iPhone's security is the ability to create better passcodes. In this day and age, it is highly suggested to include letters and numbers in your passwords to make them more secure. If your not using a alphanumeric password for your accounts already, go and change them now.
Well thanks to the folks over at 9to5mac, they have compiled a mobileconfig that you can load directly from Safari on your iDevice, and you will simply be prompted to enter a new passcode and you'll see that you have the option to use letters and numbers in your new passcode. It really doesn't get any easier than this. Simply open this link, a mobile config installation will appear. Download it, then email it to your self. Next open the email on your device, download the attachment and Choose Install. Afterwards you can enter your new password.
Now let's say you want to remove it. That's simple too. Go into your Settings then over to General > Profiles >9to5mac, then click remove and confirm. You can then change your password back to whatever you had before.
Just do yourself a favor and if you decide to use this, REMEMBER your password.
Alternatively, iClarified hosts a guide that allows you to do this manually, but we don't recommend it.
MobileConfig Link (Open on iDevice)