If you've got an iPhone, life is pretty simple when it comes to apps: you get them from the iTunes App Store, or you get nothing (unless you want to hack in to your own phone.) But life is a little more complex with Android, which is based on open source technology, an approach that extends to applications. Here are some of the main ways to get and use Android apps.
Android Market
The Android market is the official Google store for apps and works in much the same way as the iTunes store. You can access it directly on your phone, though you'll need to set up a Google Checkout account for payments for non-free apps.
Amazon
Amazon.com runs its own app store for Android, though confusingly you'll need to install an app to access it. Once you've done this, you can buy apps through the Amazon website and they'll automatically show up on your phone.
At the time of writing the UK version of the Amazon store was still "coming soon". The US version is accessible if you set up a dummy Amazon account with a US address, but you'll only be able to access the site's choice of a free app each day, rather than being able to buy as well.
Other Third Party Stores
There are numerous other app stores, which work in various ways. Some allow you to buy by visiting a web page on your phone, while others install a store app on your phone. You may often find the same app is available from different stores for different prices, and there are even comparison sites.
Security
Because Android apps aren't all vetted before they can be used, there are greater security risks. There are three measures you can take, the first being to choose your app store with care. Some are more reliable than others, and reports have suggested those based in China in particular may be scams, malware distributors or both. Look for a credible site with good reviews from trusted sources.
The second step of which is to consider security software on your handset: there are similar tools to those available on desktop PCs, and some phones even come with free trials for the likes of the McAfee package.
The third step is to pay close attention to permission requests. By default an Android app can't access data from any other application or the operating system itself. Instead apps can only do this when the user has granted a "permission". This is done on a case by case basis: for example an app needs one permission to access a user's phone contacts list and another permission to send text messages. Because of this you should always pay attention when an app asks you to grant permissions and check carefully to make sure they seem appropriate and necessary for the app's stated purpose.
