I connect to my work Exchange email system with my iPhone, which necessitates a Passcode Lock. Initially, I used a secure password mixing numbers, symbols, and letters, but it proved to be a real pain trying to tap that long sequence in every time my phone locked. Naturally, I quickly reduced my passcode to a simple series of letters, but even that proved problematic because the keyboard is so small.
Recently, I noticed that fellow iPhone user had a much more manageable passcode screen. It was larger, and used only numbers. Like this:
I have not seen this documented elsewhere, but it turns out that, if you have a numeric-only passcode, the passcode screen displays only numbers. This bigger screen, with bigger buttons, is a lot easier to type in.
Yes, I know that a numeric-only passcode is not as secure as one that mixes in letters and symbols, but ease of use on an iPhone counts for a lot.
On a related note, if you are concerned about losing your iPhone, I recommend the If Found app by Mobility Ware. This free app creates a custom wallpaper upon which you can enter your contact information. If someone finds your iPhone, the screen will display a message “If Found, please contact me at…” where you can list your email address, phone number (presumably, not your iPhone mobile number, because that would be silly) and other information to help you recover your device. This, along with the new Find My iPhone service via MobileMe, should help set your mind at ease about misplacing your precious, precious iPhone.