I am sorry to post this but as a seller I was emailed by a few of my customers asking me for the 200 refund or the 100 credit.
I informed them that if there were $200 to be collected then I would collect them but as fort the $100 I probably cants due to the fact that I have sold 40 iphones that were elegible for it but i dont own 40 at&t numbers

Anyway some said OK others got pissed, but really if they spent a minute to check apples webpage it was pretty clear :

Am I eligible for the Apple Store credit if I bought my iPhone between August 22, 2007 and September 4, 2007?
iPhones purchased from Apple and invoiced to you from August 22, 2007 through September 4, 2007, are eligible for price protection. The deadline for price protection claims is September 19, 2007. You must file your price protection claims at the Apple store (Apple Retail or Apple Online Store) where you purchased your iPhone.
 If you purchased from an Apple Retail Store, visit the store where you made your purchase.
 If you purchased from the Apple Online Store, call 1-800-676-2775.
If you do not file your claim for price protection by September 19, 2007, you may submit a claim after that date for a $100 Apple Store credit via the procedure outlined at www.apple.com/iphone/storecredit. Customers who participated in Apple's price protection offer are not eligible for the $100 Apple Store credit.

Most buyers who bought from ebay dont qualify for the $200 (since they bought it from ebay and the invoice was in the ebay sellers name) . but if they are fast enough they probably can get the $100 store credit and sell it on ebay for $90 after ebay and paypal fees end up with 7x in their pocket.

This might be late as an anouncement but really it had to be said.