PowerShell Mode is an Emacs major mode for editing and running Microsoft PowerShell files.

With MELPA

First, add the package repository:

(add-to-list 'package-archives
             '("melpa" . "https://melpa.org/packages/") t)

Then install powershell.el:

M-x package-install RET powershell RET

El-Get

powershell.el is included in the El-Get repository

Install powershell.el:

M-x el-get-install RET powershell.el RET

Manually

Download powershell.el and place the download directory on your load-path like so:

(add-to-list 'load-path "~/.emacs.d/path/to/powershell")

I combined powershell.el and powershell-mode.el (last updated October 2012). I used the name powershell.el with the permission of the creator, Dino Chiesa. Since powershell.el was licensed with the new BSD license I combined the two files using the more restrictive license, the GPL. I also cleaned up the documentation and reorganized some of the code.