Posts controller...
...
#I want to allow only the post owner to be able to view "show" their own post(s)

...

# I would do this though
  def show
    @post = current_user.posts.find(params[:id])
    respond_to do |format|
      format.html # show.html.erb
      format.xml  { render :xml => @post }
    end
  end

... other basic crud methods

...