Welcome to the forum AceTracer!
The pre-approval letters sent be credit cards today mean almost nothing. Credit card companies purchase mailing lists of applicants they believe are likely to qualify and send them the so call pre-approval offers. In reality, nothing has been approved. Just think of those letters as a piece of paper that says: we think there is a possibility you might qualify for this card.
There are members on this forum age 18 and 19 who have reportedly been approved for the Zync recently, according to their posts. Reportedly some members have been approved with rather low scores. Here is a recent post by user Originality:
I have a credit score of 580-595 depending on either transunion, experian, or equifax...and i was just approved for an American Express Zync Card..i had a past collection that was recently settled in December 2009. So if i am able to be accepted im pretty sure you can too. Good Luck!
The consensus of Credit Card Forum members appear to be that the Zync card is the easiest, or one of the easiest, American Express cards to qualify for. To learn more and for a special signup bonus, check out our American Express Zync Card review
Best of luck!