Take a ride on public transport and it’s like a game of spot the smart phone. Instead of passing time by reading a paper, more commuters choose to spend time connecting, searching and playing on their web-enabled devices. Soon we will see more and usage of tablets adding to the mix of screens. Then at home and in coffee shops we’ll soon see intereactive web TV’s when screens will get much bigger.

Much has been written, including by me, about the challenge of trying to write apps for different platforms because of their different operating systems. For the business and its developers, differences in operating systems can be frustrating. Designing a successful iOS app is only half the battle. What about Android, Windows, Linux and BlackBerry?

Worst, however, is still to come. While analysts and experts concentrate on the problems of designing for multiple operating systems, they also often miss out another – potentially bigger – problem: screen size.

The increasingly crucial challenge for app developers is how to get an one to display appropriately across a range of screen sizes without having to recreate pages for different platforms. And that is a real challenge.

Large vendors have already talked about how to cope with the trend. Microsoft created its “three screens and a cloud” vision, which concentrates on how software experiences will be delivered through cloud-based services across PCs, phones and TVs.

Now Google is preparing to join the action, too. In December, details of Google’s next version of the Android operating appeared on the web. The supplier started demonstrating how the system, referred to as Honeycomb, will work across multiple form factors.

More specifically, the system promises support for higher resolutions and boasts a frame-based interface that should allow the apps to run on a phone and a tablet, while being perfectly optimised for both. The result is that developers should be able to create one application that works on a number of screens.

Apps will have fragments that a pltform can choose to run depending on screen size and apperance. The result is something like a best-fit solution; an approach to technology that will allow the user to have a consistent user experience across multiple platforms.

Dealing with multiple screens can seem an added complication to the problems associated to dealing with multiple operating systems. There is no need to panic, however. Vendors are taking steps to design component-based systems for the mobile platforms of the future.