This is answer is purely from a website standpoint.
Media querie, curtesy of CSS3, gives us more control over how a website will look at various resolutions. As you scale down the width of the browser it will swap to the code for that width.
Some info on Media Queries - http://www.stuffandnonsense.co.uk/blog/about/hardboiled_css3_media_queries
This falls under Responsive Web Design, which is the current craze.
Some info on responsive web design and media queries - http://webdesignerwall.com/tutorials/responsive-design-with-css3-media-queries
Now for the downside of responsive design - responsive/scaling images:
"Viewing a responsive website on a mobile device forces the CPU and memory of it while resizing images because you are downloading a large image, uncompressing it in your phone’s memory and then resizing it to fit a small screen. This process takes about 3 bytes per pixel of memory, so a 1024×768 image will take about 2.36 MB of memory. Most clients only request 4 images in average at the time, but 9.44 MB is still a lot for a page load. A recommended file size for images in a mobile context could be 100×100, but this is kind of utopic since a suitable image for desktop websites exceeds that resolution."
There are several solutions for this:
It is relatively new way of creating websites but there is a lot of information online from smashing magazine to a list apart.
*Edit: You will probably get a lot more answers if the question was on stackoverflow or webmasters.