Responsive Design as a Standard
Responsive design is all about thinking beyond the desktop. With new smartphones, tablets, monitors and televisions being released all the time it is impossible to create a site for each platform. The practice of responsive design consists of a combination of flexible grids and layouts, images and an intelligent use of various CSS media queries. As this practice is still in its infancy, you will need to request this feature at the quote stage of the project.
An excerpt from Responsive Design as a Standard