Jeez, do I have that bad a reputation since I'm both a tech blogger and a daddy blogger over on my Attachment Parenting blog? Seriously, I understand how difficult it is to parent in a technological age where we're surrounded by enticing gadgets full of fun games, an infinite number of movies, and access to the Internet, all a finger tap or two away. Still, it's not all about passwords and hiding your iPad and other devices, is it? :-)

Actually, I'll admit that I took advantage of your question to set a password on my own Apple iPad and plan on leaving it in place just in case there are any issues with it being used without permission in my household too.

Whatever the reason, here's how I did it on my iPad...

Go into "Settings" --> "General":

Notice that there are both "Auto-Lock" and "Passcode Lock". To start out, you want to select the latter:

The Auto-Lock lets you have the iPad automatically lock after a certain amount of inactivity. I suggest that 15 minutes is a good amount of time (it doesn't kick in if you're watching a movie, by the way).

Now back up by tapping on "General" on the top left and selecting "Passcode Lock". This is where we actually set the numeric password code:

Tap on "Turn Passcode On" and you'll be prompted to enter a four digit numeric code:

I don't need to tell you that it's quite a pain if you forget the code, so pick something that's easy for you to remember but hard for your kids to guess. An example might be the last four digits of your childhood phone number, or your own number, backwards. Obviously there aren't a ton of choices but still, four digits = 10**4 or 10,000 entries, plenty enough to keep your kids busy!

Once you've entered your key you'll be able to tweak things to set it just right:

Notice the bottom option, where you can set it to automatically wipe all the data after ten failed attempts to enter the password. I would strongly discourage you choosing that, however. It'd be quite a drag for your kids to wipe your iPad, after all!

Instead, start by tapping on "Require Passcode":

Immediately feels a bit too much, so I suggest 15 minutes, or even longer:

Set it too short and it'll drive you crazy, constantly prompting to enter the code. Set it too long and an hour after you've put it away it's still unlocked and ready to play. Part of it might depend on your usage patterns too, if you use it at work, say, and then it sits on your home office desk all night, then that's different to it being on the kitchen table 24/7.

Finally, when you do have it set as you desire, just let it sit for a while and the next time you pick up the iPad, it'll prompt you for the numeric password before anything else can be chosen:

Now, good luck with your kids. Good luck explaining why you set it up in the first place. :-)