The smartphone has become the modern day Swiss Army Knife for the resourceful traveller.

The smartphone has become the modern day Swiss Army Knife for the resourceful traveller.

Business travellers and smartphones are a match made in heaven. A few well-chosen apps can turn the modern mobile into the electronic equivalent of the Swiss Army Knife.

But with over a million apps on offer across the Apple, Google, BlackBerry and Microsoft app stores, where do you start?

A few well-chosen apps can turn the modern mobile into electronic equivalent of the venerable Swiss Army Knife. 

Here are High Flyer's list of 10 must-have apps for the Australian business traveller and frequent flyer.

1. Sydney & Melbourne airport apps

A handful of Aussie airports have their own iPhone apps, and those for Australia's two busiest airports are the best of the bunch.

There's the basic arrivals and departures information for domestic and international flights, although the Sydney Airport app doesn't support flights to and from Qantas' domestic Terminal 3 (it seems that Qantas doesn't share that data with the Sydney Airport app).

You can also see the check-in counter and boarding gate for outbound flights.

Best of all, live updates on any specified flight – such as alerts of when boarding commences and the dreaded final call – are pushed to your iPhone and appear like SMS messages on the screen.

Download: Sydney Airport appMelbourne Airport app

2. Qantas Windows Phone 7 app

Owners of the latest Windows-powered smartphones such as Nokia's new Lumia series enjoy a rare one-up over their iPhone and Android counterparts with this slick app created by Qantas and Microsoft.

It offers a start-to-finish experience for your flights on the Red Roo, from mobile check in (complete with a mobile boarding pass on your phone) to help with baggage drops, finding the airport lounge and reporting the weather at your destination.

But the winning feature? Live updates which sit right on the smartphone's home screen, so you can keep an eye on your flight without having to open the app.

You can even 'pin' individual flights to your start screen to help juggle multiple segments of a trip.

Download: Qantas Windows Phone 7 app

3. Frequent Flyer Calculator First Class

Created by Adam Ware, an Aussie frequent flyer and iPhone developer from Brisbane, FFC is the ultimate manager for your Qantas Frequent Flyer points – and better than anything Qantas offers.

It lets you work out how many Qantas Frequent Flyer points and Status Credits you'll earn on domestic and international routes, based on your travel class and current status.

This includes complicated itineraries which span several flights with Qantas and oneworld partner airlines like BA, American Airlines and Cathay Pacific.

You can also track how many status credits are needed to climb to the next tier, such as Gold or Platinum.

Download: Frequent Flyer Calculator First Class

4. Award Wallet

Still on the topic of points and status, most business travellers and frequent flyers belong to a score of airline and hotel loyalty schemes.

Award Wallet – a free and independent online service with companion iPhone and Android apps – lets you track them all and keep an eye on points that'll soon expire.

Setting up Award Wallet takes some time because you need to enter your user name and password for every reward scheme.

However, if you simply want to keep a handy list of your membership numbers, to save carrying around dozens of cards, I suggest entering each number into your smartphone's address book. Use the reward scheme as the company name and put your membership number in the notes field.

5. TripIt

TripIt provides an amazing way to organise all your travel into a single master itinerary.

It's a free online service with apps for the iPhone and iPad along with Android, Windows and BlackBerry smartphones.

Instead of manually entering your flights, hotel bookings and car hire details into your calendar, word processor or spreadsheet, you forward the confirmation emails from each booking to your Tripit account.

TripIt automatically extracts the relevant details and pulls them together a single detailed itinerary, along with extras like weather and maps.

You can sync your itinerary to Google calendar, Microsoft Outlook or Exchange, or Apple's iCal, and print it out as a backup.

6. Evernote

This is one of those apps which almost any smartphone user will appreciate, but it's especially handy when you're on the go.

Evernote is a cloud-based service which stores notes, photos, even voice recordings and whole web pages online.

You can enter, update and search for notes using Evernote apps for your desktop or laptop as well as iDevices, Android mobiles and tablets, and BlackBerry and Windows Phone 7 smartphones.

I find Evernote invaluable for odds and ends during my travels such as shopping lists and snapping and saving photos for later reference (such as the label of a particularly great bottle of wine).

7. Currency

Among scores of iPhone currency convertor apps, Currency remains my favourite because it's simply the quickest and easiest to use.

And with the ability to keep seven of your most commonly-used currencies on the screen it's ideal for frequent flyers.

Download: Currency

8. Skype

Travelling overseas and need to call home? Fire up Skype and use your hotel's in-room wireless or a cafe hotspot as a surrogate mobile phone network to avoid those sky-high roaming charges.

Load up your Skype account and use pay-as-you go for calls to landlines and mobiles or grab an unlimited call plan starting at $8 per month.

However, Apple users should note that Skype videochats aren't anywhere near as good as what you can enjoy over FaceTime.

9. Yelp

I've become a convert from UrbanSpoon to Yelp. Both offer crowd-sourced reviews of local cafes and restaurants based on your current location, thanks to the iPhone's GPS, but Yelp goes further by adding other types of businesses. It's one of my regular go-to apps in an unfamiliar city.

10. Top Shelf Drinks

Thirsting for a cocktail at the airport lounge or a hotel's club room? For a tiny $1, Top Shelf Drinks for the iPhone shows what you can create from the limited selection of liquors and mixers on hand. On Android, the $1.49 Mixologist guarantees the same result.

On top of those ten apps come a bunch of city-specific favourites, of course. I love the Best Coffee family of iPhone and Android apps to discover the top brews in London, San Francisco and New York; KickMap for finding my way around New York's subway labyrinth; and The Scoop for a hot list of restaurants, bars, coffee shops, stores and more curated by The New York Times.

What are your favourite business travel apps, both on a global basis and for specific cities?

David Flynn is a business travel expert and editor of Australian Business Traveller.

Twitter: @AusBT