Dl the bootanimation.zip that you want (I have some cool ones if you need)
Boot anims are kept in either data/local or system/media so use root explorer or another root file manager to access these folders.
Take the new animation and place it in system/media (make sure it is named bootanimation.zip and that it's the only file of that name in system/media or data/local.
Reboot and enjoy your new animation!
If you have any more questions, send me a pm and ill walk you through it.
D2
You and your manual ways! Seriously though, it's great to know how to things the hard way, but I sure love any app or util that makes customization easier. You know?