Apple care can be added with customer care with in 24 hours of activation of the device or at time of purchase.
After 24 hours it can still be added within 30 days of original purchase date at an Apple Retail Store, where phone can be visually inspected and checked for proof of purchase.
After you get your iPhone, I believe that you can still purchase Apple Care+ in both Apple and Sprint Stores, as long as you do it within the first 30 days.
This helps alot. They told me today it was NOW OR NEVER! They noted my account that I refused Apple Care. I never said that. I just wanted more information.
Here is an excerpt from the article that should hopefully be helpful. (I believe this is the option I'm going to take since I don't want to go anywhere near an Apple Store after an iPhone release!)
AppleCare+ will be available for iPhone 4 (8GB) and iPhone 4S pre-order customers until November 14th. After you receive your new iPhone, please contact AppleCare (1-800-275-2273) to complete your purchase.
Rachel Apple Inc.
I spoke with an Applecare+ representative on Monday because I did not purchase the insurance when I purchased my iphone on Friday. I was told there is another email that you will recieve inviting you to complete your order. The email will offer you an opportunity to purchase Applecare+ at that time. I spoke to Sprint first and was told you could not purchase if you did not purchase it during the time you purchased the iphone. Hope this helps.
I am 99% sure that you can order it through AppleCare+...I think I read somewhere that if you email them, they will get back to you relatively quick. I know some states don't have Apple stores at all.
I read that Apple extended AppleCare+ orders to November 14 for pre-orders, so if you want it now, but didn't order it when you ordered your iPhone 4 or 4S, you should still be able to get it.