Backup your contacts from your iPhones and iPad

http://www.google.com/support/mobile/bin/answer.py?hl=en&answer=138744

Basically, connect your device to the computer (Mac or PC) that has
iTunes on it. Then upload the info onto a Gmail account. Notice, this
Gmail account is not your main Gmail account, but a "backup" one. A
backup Gmail account is basically an account that acts as a secondary
depository for your info. This way, if any thing bad happens to your
main Gmail account or your device like a bad sync that wiped out some
or all important info, you would go to this backup depository Gmail
account to resync.