[By Duncan McLeod]

Google’s Android Market, Apple’s App Store, Nokia’s Ovi Store and BlackBerry’s App World together offer hundreds of thousands of free and pay-for apps. But finding the diamonds in the rough is often hard. These are some of my free favourites that run on both Android and Apple’s iOS.

WhatsApp Messenger: This cross-platform instant messaging service has taken off like wildfire — and that’s not surprising since it’s a free (for a year) replacement for SMS, provided your friends are using it (and many of them are). The app lets you chat with your friends and family, see when they’re online and even share images and audio and video clips with them.

Kindle: You may or not own an Amazon Kindle e-book reader, but the app for smartphones is a must-have either way. It downloads and syncs the books you’re reading between devices, so next time you’re standing in a queue, why not kill some time reading that e-book you just can’t, err, put down?

Skype: Everyone knows Skype for Windows or Mac, but the voice and video calling program also runs on a range of smartphones and now on the iPad, too.

Soundhound: Listening to a song on the radio and would like to know what it is? Run this app and it’ll upload a small audio sample and tell you in just a few seconds and offer you the ability to purchase the song or read the lyrics. You can even hum a tune to it, and some of the time it’ll get it right. Also, check out Shazam.

TuneIn Radio: Listen to thousands of free, streaming radio stations from around the world. Stations are grouped into categories — music, sports, talk — and the app makes suggestions about stations based on your location. See also Slacker Radio and Pandora.

Google Reader: Subscribe to and read your favourite news sites using Web feeds. The app makes it easy to filter news that matters to you and syncs across your Reader accounts.

Sharenet: This is a great SA app that lets you check on the stock markets, including JSE and world indices, get delayed stock quotes and set up watch lists. Also check out the free Bloomberg app.

Google Maps: This is simply the best free app for maps available to SA smartphone users. It includes Google Street View and, if you have an Android device, offers turn-by-turn navigation. Now if only it would offer real-time traffic data.

Sky Map: This one works on Android only, but it’s worth including here. A must for astronomy geeks, this Google app uses the digital compass and GPS in your smartphone to turn it into a “window on the night sky”. Simply point your phone skyward to see what constellations or celestial bodies you’re looking at. On iOS, check out Star Chart (US$2,99).

Picplz: Quickly take and share photos with friends, applying a range of special filters and effects on the go. Also take a look at Instagram if you have an iPhone.

TweetDeck: The official Twitter application is good, especially on the iPad, but TweetDeck is arguably still the king of the tweeting jungle on smartphones.

FNB app: This transactional banking app, which runs on a variety of smartphone platforms, shows First National Bank is leading the consumer technology pack among the big four. Word is Absa is planning one, too. Apparently Standard Bank already has one – good luck finding it, though.

Zinio: Easily the best app for subscribing to and reading magazines on your tablet or smartphone, Zinio has thousands of titles to choose from, including a growing list of SA publications. Best used on a tablet, it’s also quite acceptable to read Zinio magazines on the latest large-screen smartphones.