This will show you how to create standalone desktop applications from a website using fluid.app

1) goto fluidapp.com
2) download and install fluid
3) open fluid

once fluid is open then simply type the url and a name for your app.
it will magically appear in the dock and you now have a standalone app for whatever site it is you want.

I use it for google reader (and for updating my site :)

there is a feature in chrome in linux and windows that lets you ‘create application shortcut’ but its not available on osx yet, hopefully it becomes available soon