added installation instructions through npm

@@ -10,6 +10,8 @@ FAQ
    :local:
    :backlinks: top
 
+.. _faq_node:
+
 .. index:: Node.js
 
 Is CasperJS a `node.js <http://nodejs.org/>`_ library?

@@ -53,6 +53,23 @@ If you have already installed casperjs and want to have the last release (stable
 
 Upgrade only update to the latest release branch (1.0.x|1.1-dev).
 
+Installing from npm
+-------------------
+
+.. versionadded:: 1.1-beta3
+
+You can install CasperJS using `npm <http://npmjs.org/>`_::
+
+    $ npm install -g casperjs
+
+.. note::
+
+   The `-g` flag makes the `casperjs` executable available system-wide.
+
+.. warning::
+
+   While CasperJS is installable via npm, :ref:`it's not a NodeJS package <faq_node>`.
+
 .. index:: git
 
 Installing from git