If I send someone a MobileMe box do they have to have a credit card to sign up for the service?

I think the point of the box is that it’s a pre pay for your subscription. But call apple they will be able to tell you for definate. Number varies on your country but apple.com has the details (usually at bottom of store)

Hope this helps, a bit.

That’s how Apple rolls.
A debit card should work.

No, you don’t need a credit card. I used a box to sign up. There’s an activation number in the box that you enter. I still haven’t entered my card details, and won’t bother until I have to renew.