Can you leverage the same central website for use with computers, tablets and smarphones all from the the same central system? The answer is YES, but there are things to take into consideration.
There two ways to develop for small screen and mobile devices: Responsive design and Adaptive design.
Adaptive web design is based on the ability of the receiving web server to detect the screen size and other capabilities of the device connecting to the service. Based on this knowledge the web server will try to create the best ways to send the appropriate information and the best way to present it. It will generate the html reply and return this to the client.
This is a server based process and depending on how many types of devices and screen sizes you want to support, not to mention any 'special' features each device may have, this can become a costly process to setup and maintain.
Responsive web design is based on dynamic re(sizing) and flow of html web page. Often refered to as 'grid' design, the web page is divided into various columns that contain the information. Using a feature of CSS3 called media queries, the webpage itself can detect the size of the screen and adapt itself on the clients browser.
Responsive design can be seen as a 'one-size-fits-all' development with a single site to maintain. The CSS can always be adapted and changed to suit new and different screen sizes. This is the most cost effective way of making cross-device web pages.
Mobile ticket sales.
Self service mobile marketing.
Mobile food app.
Digital business cards.
Mobile Internet tools, utlilities and services.
Depending on what technology is currently used in your webiste, you may need to make some changes.
iPhone users cannot use Flex and Flash, so if your site relies on this technology to operate you will either have to replace it with another technology that is supported across all platforms.
If you provide services that require large screens, this may not scale down well for small screen devices, think of an online text processor with rich functionality as example.
In such cases alternative methods that are mobile friendly will need to be developed and deployed, or you may need to remove these features for mobile users.
Computer websites with complex and compound navigation or services rely on a mouse pointer to accurately move and make selections on a large screen
Mobile devices on the otherhand have small screens and the only pointing device is a fat finger. Navigation and operational acitivity on your website may need to be adapted to be made suitable for both.
Let's say for arguments sake, all the points above apply to your site in a non-mobile friendly way. Your option is to develop parallel to the existing website and/or create native apps.
Which platforms to support?
IOS - iPhone and iPad applications
Android - Phones and tablets
Three times the cost in the end.
Most modern mobile devices and smartphones have onboard GPS (Global Positioning System) that if enabled can provide the latitude and longitude of when the device is physically located.
Using HTML5 and smartphone GPS position enables the ability to utilize various smart features and services. One of these is active real time navigation.