Such a short question can mean so many things to different people. This is how I interpret your question:

"Should I build solutions for my customers/employees/others that are dedicated to providing a mobile solution, or should I just stick to my current web or client/server applications"

I could have written the above a hundred different ways, but the answer in short is "yes", but that is not really the answer you need. It is about minimising risk and growing the solution over time.

For example, if you currently have solutions that are on the desktop or on the web, you can build a "WebApp" that is effectively a web application that is optimised for the mobile. Languages like JQuery Mobile, DOJO and many other Javascript derivatives can help that. Combining that application with technologies that report how the app is used and the response times achieved (the biggest weakness of WebApps) will be key inputs into building a dedicated mobile computing solution.

There are many paths to a dedicated mobile computing solution, but the key to what path to take is understanding the geography and user base you are targeting. If that is in Australia, it is likely to involve an iOS/iPhone/iPad platform initially due to its current dominance, but Android is growing and that is likely to be the 2nd platform targeted (note that the WebApp can target all HTML5 based platforms, so this is an ideal backup as you rollout multiple platforms). Windows8 will take time (anywhere from 6 to 14 months is significant time in the IT industry) before it becomes a real presence that must be considered.

But these decisions can change drastically depending upon what you are targeting. Either way, the key is to take a broad approach through a WebApp and phase in dedicated solutions - where they make sense.

A key point worth considering when thinking of dedicated mobile applications is integration. Typically, business applications rely on centralised data - whether that be to share data across devices through a user account or to share data outside of the user themselves. This design aspect is important as devices are not always "online" and you also do not want to suffer the same performance drawbacks that a WebApp can suffer from. Therefore, you will require some local storage and integration back to a central point. This can make a seemingly cheap and easy idea into a logistical nightmare, and this is where professional experience will turn the potential nightmare into a reality - just not as cheaply as you first imagined !!!

So broadly speaking, to recap the answer, yes, you need to invest in mobile computing, but only after you have considered what the use is and who by. Then take a softly-softly approach by first incorporating WebApps, then where it is justified, deploy dedicated solutions.

The exact use you require may dictate variation to the above simple explanation, but as a generic approach, I believe this will help you move your strategy forward. I would love to hear more about exactly what you were contemplating around mobile computing. All the best.