If you purchased an iPhone and have not activated it with AT&T you won't be eligible for Steve Jobs' Mea Culpa US$100 rebate for early adopters.
If you read the fine print on Apple's freshly posted store credit page you'll see that anyone not registered with AT&T (i.e. unlocked phones) will not get a rebate.
The process goes like this:
Step 1: Identify your iPhone
To confirm eligibility, simply enter your phone number and iPhone serial number in the fields provided.
Step 2: Enter your access code
You will receive an SMS text message on your iPhone containing the access code to redeem your $100 credit. Enter your phone number and your access code in the fields provided to generate an electronic store credit.
Step 3: Get your $100 Apple Store credit
You will receive a $100 electronic store credit to purchase products at the Apple Retail Store or the Apple Online Store.
After completing the short process (about three minutes) Apple provides you with a printable coupon that can be redeemed at an Apple Retail Store or entered during checkout at the Apple Online Store.
Requests for the $100 credit must be submitted by November 30, 2007. A frequently asked questions list is also available.
Jump for the rest of the T's and C's:
Terms and Conditions for the $100 store credit for Early iPhone owners program
This credit is extended to end-customers who own a qualifying iPhone purchased from Apple or AT&T prior to August 22, 2007. To receive a credit, customers must submit requests between September 13, 2007, and November 30, 2007, at www.apple.com/iphone/storecredit. Requests will not be accepted after November 30, 2007. The program is for a $100 Apple electronic store credit in the form of a numeric code consisting of a credit number and PIN. This program is limited to one $100 Apple electronic store credit per eligible iPhone. Customers may apply this credit as provided in these terms and conditions. Customers should record the numeric codes that are presented electronically through the web browser. Apple will not replace lost or stolen codes. Only iPhones activated through AT&T are eligible to receive a credit.
Some iPhones will not qualify for a credit. They are: (1) iPhones purchased from Apple from August 22, 2007, through September 4, 2007, as they are subject to price protection (Separate terms and conditions apply. Details are available at www.apple.com/iphone/storecredit/priceprotection), (2) iPhones that have been returned to Apple or AT&T, (3) iPhones for which a Gift Card, rebate, or other consideration have already been issued, (4) iPhones that Apple provided to employees, either for personal use or for departmental use, (5) iPhones provided by Apple for product reviews, (6) AppleCare Service iPhones, (7) iPhones registered to customers whose addresses are outside the United States, (8) iPhones for which Apple or AT&T already has extended price protection under applicable sales terms, and (9) iPhones purchased by corporations or education institutions where Apple has provided alternative accommodation.
Customers may redeem their store credits only for qualified purchases directly from Apple at an Apple Retail Store, the Apple Online Store, or Apple Telesales (1-800-MY-APPLE) in the United States. Customers may not redeem their store credits: (1) at any iTunes Store in the United States or elsewhere, (2) Apple Store locations outside the United States; (3) at Apple resellers; (4) for cash; (5) to purchase Apple Gift Cards, or,iTunes Store Gift Certificates, to give iTunes Store content as gifts, or to create iTunes Store allowances; or (6) as payments on Apple accounts. Customers may not resell, transfer, or otherwise assign the credits. Remaining balances on store credits can be determined by calling 888-320-3301. This store credit program is governed by the laws of the State of California. Apple reserves the right to deny or disregard any claim deemed to be false or fraudulent. This program is valid only to customers who reside within the 50 United States or District of Columbia. This program and the store credits are void where prohibited or restricted by law. Apple is not responsible for printing or database errors. Customers should keep copies of these Terms and Conditions. Apple reserves the right to change without notice the Terms and Conditions, modify the program, or end the program at any time.