What used to be considered a feature and an extra function of a website has now become the norm, welcome to the responsive web design era.
We have been experimenting with many different forms of responsive design including jQuery mobile, various WordPress plugins, and custom coding. I have just recently found 3 resources which are great and have been using for our responsive design templates.
Responsive Retina Read Menu (A simple fun menu)
Osvaldas Drop-Down Navigation (More robust, for larger more complex websites, dont use with 3 level navigation)
Mobile Detect PHP Class (Awesome script)
As I find more resources I will be posting them here.