Can I make an auto-lock message?

There are apps in the app store that work by displaying your contact details on the lock screen, so if you ever lose your phone and the person is honest you have a better chance of having your phone returned. I can't remember the names of the apps but I'm pretty sure you'll have no trouble findin them in the app store, I think under the utilities section. There are several that do this, so you shouldn't have 2 much trouble.

Three apps that accomplish the same thing in very different fashions. Take your pick as to which one you like. I think the one that best fits what ur asking for is Lost Phone. There is also My Info and Motion Alarm and as I said it's really a matter of what best suits your needs, as they all accomplish what you're after but do it in very different ways. This is by no means a complete list of apps that do this, this is just to give you an idea. There are plenty of apps that do this you just need to look. Try search and punching in some keywords 'cause doesn't just search app titles. It also searches through the descriptions.
Anyways I hope this helps

Use an image editing progam to make your own wallpaper with contact info. Mine says:

$ REWARD $
danxxx@xxx.com
wife's cell number
my landline

For anyone who might think this is a waste of time, I had four GPSes and my MacBook stolen in a housebreak this past summer. Police recovered the laptop and all but one GPS. It was the only device that lacked this kind of lock-screen display. Pawn shops often won't buy stuff that is "marked" this way.

-dan