There's no doubt that the technology made available to us through smart phones and Apple's iPhone keeps us more in touch with the world. But there's a problem when the world wants to be more in touch with our iPhones, if you know what I mean. Identity theft is a major issue in this paperless age of ours, and if you want to make sure that your iPhone is protected, it starts with a good password.
First, you'll actually want to turn the password feature on your iPhone on. It can be a little obtrusive, but if you turn this feature on and forget about it, soon it will simply become a part of routine that you don't notice quite as much. In order to turn the password feature on, you'll have to write a solid password.
Go to Settings > General > Security lock, as TUAW will tell you, and from there you'll be able to work on setting your passcode - but this isn't your password. It's actually a passcode, a four-digit code you enter in, much like a PIN number.
It's fine to have a PIN number, but if you want to replace your password with a more traditional alphanumeric password (that is, using letters/numbers), then check out this guide from iPhone Download Blog.
After you follow the instructions in that blog post, you'll be able to set an alphanumeric password.
There are a couple of things to keep in mind when you set your password. Many people prefer to have their password something they'll easily remember, like a mother's maiden name or their favorite pet. But having a simple, easy-to-remember password does put you at risk at someone being able to figure that password out and hack into your iPhone.
We recommend that you try to set a more difficult password, such as a random collection of letters and numbers. This can be a little difficult to learn at first, but once you have this number memorize, you'll have it locked safely in your mind for a long time, that is until you change your password again. At the very least, incorporate some numbers into a more traditional "word" password so that even people who know you well won't be able to figure it out. If you're well-known for loving cats, then "cats" isn't a great password, but "cats14022" is much more difficult to figure out.