Document raw module.

rst/modules.rst

@@ -319,6 +319,26 @@ any changes on the system.
 
 .. _service:
 
+raw
+```
+
+Executes a low-down and dirty SSH command, not going through the module subsystem.
+This module is new in Ansible 0.4.
+
+This is useful and should only be done in two cases.  The first case is installing
+python-simplejson on older (python 2.4 and before) hosts that need it as a dependency
+to run modules, since nearly all core modules require it.  Another is speaking to any 
+devices such as routers that do not have any Python installed.  In any other case,
+using the 'shell' or 'command' module is much more appropriate.
+
+Arguments given to 'raw' are run directly through the configured remote shell and 
+only output is returned.  There is no error detection or change handler support 
+for this module.
+
+Example from `/usr/bin/ansible` to bootstrap a legacy python 2.4 host:
+
+    ansible newhost.example.com raw -a "yum install python-simplejson"
+
 service
 ```````