[ame=http://www.youtube.com/watch?v=UzDMSenVRPU]YouTube - Custom BOOT LOGOS On iPhone And iPod Touch - iOS Vlog 283[/ame]
Apple Boot Logo is a free tweak that will enable you to change your boot logo on your iDevice. Most devices are supported, everyone should have a 2G,3G, or 4G device by now. The tweak is easy to use, however if you want to make your own boot logos it will get a bit tricky(video coming soon). There are plenty of boot logos you can find in Cydia already. Got ahead and search "boot logo" or "boot" in Cydia, and you should find some that work with Apple Boot logo.
Supported:
iPhone 4
iPhone 3GS
iPod Touch 2G
iPod Touch 3G
iPod Touch 4G