Also Following website looks like under construction
Do we have any another website.

I want to build kernel for beaglebone, but will start with beagleboard as it seems like the proceedure is documented better. If I could find the current build instructions, that is. I get this:

Obsolete - follow the instructions from instead

Clone the setup scripts repo, ./ config beaglebone, ./ bitbake cloud9-image

To clone the setup scripts repo Koen is taking about do:
git clone

... then run the shell script as he described.