Added notes on how to install and a link to the PIP package.

Author: joestump

README.md

@@ -11,6 +11,14 @@ This code was originally forked from [Leah Culver and Andy Smith's oauth.py code
 * The library is likely no longer compatible with Python 2.3.
 * The <code>Client</code> class works and extends from <code>httplib2</code>. It's a thin wrapper that handles automatically signing any normal HTTP request you might wish to make.
 
+# Installing
+
+You can install `oauth2` via [the PIP package](https://pypi.python.org/pypi/oauth2). 
+
+    $ pip install oauth2
+    
+We recommend using [virtualenv](https://virtualenv.pypa.io/en/latest/).
+
 # Signing a Request
 
 ```python