A tiny eshell add-on: jump to shell ready to take input

So I'm finally grokking eshell and one feature I want is the following:

Suppose I'm looking at a buffer containing index.html which lives in ~/projects/hacking. I'd like to effortlessly switch to eshell and have it jump to this directory, so I'm ready to start entering commands.

If I had this feature in place, I could go from a file's buffer to a shell quickly and without futzing with changing directories. Using this example I was able to quickly write up a command that does exactly what the above description suggests:

;; Inspired by: http://www.emacswiki.org/emacs/EshellControlFromOtherBuffer
(defun bs-eshell-switch-to-and-change-dir ()
  "Switch to eshell and make sure we're in the directory the current buffer is in."
  (interactive)
  (let ((dir default-directory))
    (let ((b (get-buffer eshell-buffer-name)))
      (unless b
        (eshell)))
    (display-buffer eshell-buffer-name t)
    (switch-to-buffer-other-window eshell-buffer-name)
    (end-of-buffer)
    (unless (equalp dir default-directory)
      (cd dir)
      (eshell-send-input)
      (end-of-buffer))))

(global-set-key (kbd "\C-c \C-s") 'bs-eshell-switch-to-and-change-dir)

From any buffer I can hit Control-c Control-s and bam! I'm now at a shell prompt ready type away.

Update: One of the comments below suggested shell-pop-el as a pre-existing implementation of the above concept. I'd definitely recommend using it over what I've got above.

Update: And try: shell-switcher, too!