Bootanimation.zip can be createdfrom gif easily now with one tool. It can be downladed at Modaco forum here . If u dont have Modaco acount and lazy to register to it, it can be downloaded here . First install imagemagick on your Ubuntu or other distro that you use.
After that just extract that zip and see its contain like this:
First read README.txt. It have do.sh , ball.gif and desc.txt. Desc.txt is a file in a bootanimation.zip which control bootanimation frame and resolution. So lets open it.
240×240 is for my devices, ldpi, 320×240, so if u have bigger, Just change 240×240 to your bootanimation resolution.
After that look on ball.gif. You can change it with another gif. That is bootanimation source. After that just write on terminal
it will be like this :