I just noticed that there will be a 3rd edition of iOS Programming: The Big Nerd Ranch Guide due out in March. I have just started developing an iPhone app and am needing a iOS programming book. I have used the Cocoa programming book for years and so will likely buy this book as well.
My suggestion is that it would be great it I could get a copy of the 2nd edition of the ebook if I prebuy the 3rd edition of the ebook. I know there are some logistical challenges to this (though since most people doing this would be using an iPad (vs. Kindle, etc), delivery as ePub from a private single use link would be possible. Because of the 3rd editions imminent release, I’m clearly not going to buy the 2nd edition, so it would likely not hurt sales either.
Anyway, just a suggestion.