The last time I always hear of new devices (Android OS, Kindle OS, Chrome OS etc) that are built with the linux kernel. I have seen the Kernel source online and also understand the basic OS theory but what I do not understand is how would I take the Kernel code and use it to start building an OS. Also how would I then boot it to a device? What kind of compiler would I use?

Thank you in regards

Have a look at Linux from Scratch