I would like to share my knowledge with you about android.
> What are the major components/layers? -Applications
>Android simply a Linux kernel with a custom Java Virtual Machine? -Linux Kernal - 2.6 with Dalvik VM
>What access do you have to the base linux kernel? Applications are written in C and provide Java interface to manage them.
>How is this linux kernel different than a typical desktop or server linux? It is the linux kernel with a extra few patches on top of it.