launch/run IPython in emacs buffer

[Tom Roche]

I can run IPython in an emacs buffer, but would appreciate help with
either of 2 problems:

0 opening an IPython buffer "from anywhere." I can open IPython in an
  emacs buffer with the sequence

* open buffer on a python file, e.g. C-x C-f /tmp/py.py
* C-c !

  This seems to work appropriately, e.g. M-p scrolls IPython history.
  However

* I'd like also to be able to open an IPython buffer from anywhere (in
  emacs), since I often use IPython as a calculator and scratchpad.

* I don't know of an existing command or config that does this.

* I don't know enough elisp to do this.

  Hence I'd appreciate a pointer to an existing command or config, or
  some elisp (or both) that will open an IPython buffer from anywhere in
  emacs.

1 fix M-p in IPython in shell-mode. When I run IPython in emacs shell
  mode (i.e. running `ipython` from a prompt after running `M-x shell`),
  IPython runs (with correct prompt, thanks Andrew Wilson). But when I
  attempt to scroll IPython history (with M-p at the IPython prompt), I
  instead get bash history. Is there a way to make shell-mode pass the
  M-p event to IPython?

FWIW, I'm running

Ubuntu 10.04.1 LTS, GNOME, 64-bit
GNU Emacs 23.1.50.1 from ubuntu package=emacs-snapshot
IPython 0.10 from ubuntu package
python-mode 5.1.0 from https://launchpad.net/python-mode/
Python 2.6.5 from ubuntu package

TIA, Tom Roche <Tom_Roche@pobox.com>