iOS: Packaged foods include nutritional information such as fat and salt levels, but it's often in tiny print that's hard to read. FoodSwitch lets you scan the barcode on groceries using your iPhone camera and then displays key nutritional data on screen.
The big advantage this app (developed by health insurance provider Bupa) has over similar rivals is that it covers Australian products. The developers claim more than 20,000 supermarket foods are included. Each lists total fat, saturated fat, sugar and salt content. In some cases, it will also suggest a healthier alternative from the same category -- a useful way to improve your diet. You can also use the app to keep shopping lists of your preferred products.
Right now, the app is iOS-only, but an Android version is in the works.
FoodSwitch [iTunes App Store]