Question
Is it expensive to make a mobile website and what about my existing one?

Answer

Provided that your existing website is in a suitable system already it is a relatively painless add on to enable your website to display across most mobile phones like the iphone, blackberry, and android platforms. The site will also intelligently recognise when it is being viewed on a laptop or a desktop.

Answer
You can always find out whether or not it is necessary or not by looking to see how many searches are being made on mobile devices as opposed to desktop or laptop computers by using the Google keyword tool.