Added link to library build instructions

README.md

@@ -81,6 +81,7 @@ More? [#three.js on irc.freenode.net](http://webchat.freenode.net/?channels=thre
 ### Usage ###
 
 Download the [minified library](http://mrdoob.github.com/three.js/build/Three.js) and include it in your html.
+Alternatively see [how to build the library yourself](https://github.com/mrdoob/three.js/wiki/build.py,-or-how-to-generate-a-compressed-Three.js-file). 
 
 ```html
 <script src="js/Three.js"></script>