What is there was a mobile phone application that could help travellers find out if their taxi drivers were cheating? You would simply add your starting point, your destination and then the app would sound an alarm when the chosen route deviates much from the shortest possible route. This would be especially useful to users who are in cities they are unfamiliar with – or where cabbies are known to take you for a ride.

iPhone and iPod touch can control iTunes libraries via a wireless network. Turns out that is a very useful tool.

What if these devices could also control a user’s Mac over a local area network or even a wide area network? It would be great to at least have access to a documents folder or at least sharing a screen.

===UPDATE 01/24===

Just noticed that the Apple app store contains a new application for iPhone/iPod touch that allows the mobile device to connect to the new Keynote ’09 to control it over a wireless network. Useful, as the slides appear on the screen, is flicked with your thumb over the touch screen and your presentation notes appear nice and legible alongside the slides.

There is no doubt that the iPhone/iPod touch pairing with the Mac is going to yield plenty of possibilities.

Evernote aims to become humanity’s memory. They have developed some awesome tools for capturing and scanning snippets of things and storing them in a cloud where you can access them from anywhere. You can use mobile devices’ cameras to scan business cards, record voice notes and take screen captures.

A great add-on feature would be to use mobile devices with built in GPS to record and track routes. Simple start/stop buttons would start storing a route and then allow you to tag them later. Or just pinpoint a position for a place you want to remember for future reference.

There is a need for travellers to be able to download and save temporary address books to their mobile devices – once they arrive in a city. These books can contain numbers of local restaurants, attractions and emergency services. In the case of some smartphones like iPhone, maps could be added. When they leave, they simply erase that set of numbers.

A useful iPhone would be one that allowed creative professionals to be able to store examples of their creative work on their iPhone/iPod touch and to display it quickly and simply. So, a slide-show viewer, combined with a video player and could even sport the name Elevator Book.

You never know who next you might get into an elevator with, do you?

The paradigm will be for apps to be created that users pay to use. What if companies could reverse the paradigm and think about apps that they would pay people to use?

Imagine a bus company creating an app for an iPhone-like device where users can give them useful information. A simple application that simply records the user’s location (using the built-in GPS), where they want to go and the time. With these three bits of information, a time, an origination point and a desired destination, the bus company will very quickly get a very good idea of how to improve their routing system.

Plus, the information is always dynamic so the routes can change with the changing needs of a city. This will undoubtedly help commuters, and importantly, help the bus company to cut out wastage and improve profitability.