Gizmodo spoke with AT&T and found out that the mobile carrier will require current AT&T customers to be eligible for an upgrade before they'll hand over the iPhone 3G at its subsidized price.

Unlike the current iPhone, that was unsubsidized, the iPhone 3G will be treated like any other mobile device the carrier sells. So what is the unsubsidized price of the iPhone 3G? AT&T isn't saying, or doesn't know.

Currently, AT&T allows customers to upgrade after two-years of service. Certain customers can upgrade sooner if they meet certain criteria. Such as, you have a calling plan that costs at least $68.99 a month but no more than $98.99 a month and have ben in contract for 21 months without an upgrade,

or

A standard calling plan plus data service costing $99 or more a month, and haven't upgraded in the last 12 months.
or
A customer with a calling plan with data service of less than $69 who is 21 to 23 months into their contract may upgrade for a fee and new two-year commitment.

Okay, who's confused?

If you have AT&T, sign in to your online account and you can check your eligibility for an upgrade, or when you will be eligible.