One of the more obscure settings that many users don't set is the "Encrypt Backup" setting, which is found in iTunes. This setting even applies to the new iCloud service in iOS 5. This setting ensures that the backup of your device is encrypted. It goes without saying, if you can access this backup, the data on your device can be accessed and harvested. For example, earlier this year there was a "feature" in which Geolocation data could be easily harvested from the backup file. This has since been remediated, but just think how much information could be harvested about you through an unencrypted backup file.
Keep iOS Updated
Making sure that you always have the latest version of Apple iOS on your device is important because Apple is always releasing security updates and implementing new security controls. Simply plug your device into iTunes and you will get prompted to update your phone to the latest version. As a side note, don't Jailbreak your device! Jailbreaking makes many of the built in security features useless and allows your device to be an easy target for data theft.
Ensuring that you have enabled and configured these security settings on your Apple iOS device is more important than ever. Devices like these are lost or stolen all the time and without taking the proper precautions, your data could be vulnerable. Having conducted Apple iOS device penetration testing assessments at SecureState for our clients, I can tell you how easy it is to break into these devices. It's easy because the proper basic precautions were not taken. Take five minutes now and enable these settings; you'll be glad you did.