How to Secure the Data in Your iPhone
Use a password: Many users don't know that the iPhone and the iPad can have passwords. This is a very simple security measure, and can be applied almost instantaneously. You just need to define a password in the settings application.
To do this, in the home screen, select Settings. The tap on the "general" option. You will see that password is one of the options available. Just enter a password there.
Now, the next time you start the iPad you will see that the same password is required to use the system. This will make sure that no random person that just open and use your iPhone.
If you have a password use a better one: Another failure from the part of users is to employ a very simple password, that can be easily guessed. For example, if you're using your own name or a simple variation as the password, some one can easily guess it too.
To avoid this problem, use good passwords. They are usually a mix of upper case and lower case letters, plus numbers and symbols. If you do this, the chances of having someone guessing your password are really small.
Some other safe ideas
Use a secure wallet app on the AppStore: Nowadays, there are several
applications in the AppStore that can be used to maintain passwords.
Such apps are known as keychains, wallets, or password managers. Search
for these terms in the AppStore and you will see a number of
applications that can be used to store you sensitive data with less
Use mobile me to delete data: In case the worst case happens, that is, your iPhone or iPad is stolen, you still have some protective measures.
Apple has created a system based on the mobileMe web site that can be used not only to track the whereabouts of an iPhone or iPad. The system can also remotely delete important data that you might have store in the device.
This way, you can do one of two things. First, you can track the iPhone and try to find it on the given location. Sometimes, the iPhone was not really stolen, but you lost it in some place that you don't remember exactly. With the MobileMe web system, you can track very closely where the iPhone might be. Of course, if the device was stolen, it is better just to call the police and show them the position returned by the web site. Most police departments these days are prepared to handle this type of case.
The second possibility is to use mobileMe to delete your private data. If it is the case that your iPhone is in the hands of someone that can misuse your private information, this is the best strategy. Just request the data to be remotely deleted. This works even if the device is not currently in operation. The next time it is connected to the network, Apple will detect it and and run the erasing operation.
With all these security options, the iPhone and iPad are probably the most secure devices on the market. You can make you safety system as complicated or as easy as you want. However, it is better to be prepared in case something happens. Preparation is the best insurance again such things.