Guide: How to change Bootlogos on iOS 4.2.1 iPhone 4, iPhone 3Gs and iPod Touch

Instructions:Your device must be jailbroken via NEW GreenPois0n RC5 on 4.2.1 Firmware. Need help jailbreaking your iPhone or iPod Touch? Then check out these guides.
Devices Supported iPhone 3Gs, 4 iPod Touch 2G,3G & 4G
Install Apple boot logo via Cydia