Upgrade Awards (miles + copay)
These can be requested by any AAdvantage member for AA flights (no codeshares) at the time of booking and may clear at any time once appropriate upgrade inventory becomes available. Requests cannot be made online and must be made by phone with an AA Reservations agent. As of October 6, 2009, all published fares (including previously excluded I, O, and Q overseas) are eligible for upgrade. Additional expedite / close-in fees apply within 21 days of travel, although AA elites using miles from their own accounts are exempt. Up to three segments one-way can be upgraded using a single award, and the full miles and copay will be charged if any of the segments clear. Upgrade awards are not valid on partner airlines or on AA codeshare flights operated by another airline. AAdvantage members may use their miles to upgrade other passengers and do not need to be traveling with them.

Passengers can determine which flights have upgrade inventory available prior to booking in order to choose flights that can be cleared immediately after the status changes from ‘Purchased’ to ‘Ticketed’. This inventory cannot be viewed on AA.com, but availability can be determined by calling AA Reservations (+1 800-433-7300) to inquire. Upgrades to First Class book into A inventory, which can also be viewed online with any public inventory tool, such as the KVS Availability Tool, a subscription service. Upgrades to Business Class book into C inventory, which is not publicly available but can be viewed online using ExpertFlyer, a subscription service that also offers a free 5-day trial. A tax differential charge will apply when upgrading a flight originating in France or any segment of an itinerary originating in the U.K.

Wiki: Upgrades: Upgrade Awards
AA.com: Upgrade Award Chart
FT: AA now allows I, O and Q Upgrade Awards (with some higher co-pays) (Oct 2009)