changing default shell

[Justin]

Hi,

I stopped using emacs for awhile and it seems I forgot a few things. 
Before, I remembered typing M-x to enter the name of a function which 
would allow me to modify certain environment variables for emacs. I'd 
enter the name of the function, hit enter, then emacs would ask for the 
variable name then a new buffer would open which would show the current 
value and allow me to graphically modify it. This buffer would also 
provide more information about the variable itself.

My end goal is to change the default shell to bash.

Thanks,
-Justin