I am developing a site that is tested only in Firefox and IE. Now I need to make the site accessible from mobile also.
So I need to know whether I need to calculate the time needed to shift the site. Is this created as a new application or the same application is modified?
When accessing stackoverflow.com from my mobile the design is entire changed. How is this done? Is it a separate application?
Thanks
Whether or not you need to create a new application for mobile depends on the site you have. The website at my workplace could not possibly fit on a mobile phone screen (too many frames), but other sites that have a more adjustment-friendly layout might just need a little tweak.
I would test your site on a mobile browser emulator, there are a bunch of them listed on this site.
Also, you might consider switching your firefox's user agent (here) so you can browse popular site's mobile versions, along with the source they used to lay it out.