i can confirm that you can buy squaretrade warranty after 30-days, even if you purchased from amazon.com. i was about 35 or so days out and called them, they said i have up to 90-days...unless i purchased from ebay. so i got the 3-year ADH (think i should have gone with the 2 year) but hey, it's a good buy either way. i think amazon.com has a really good price on squaretrade, the only better offers i saw was from costco.
word to the wise, get squaretrade because with asus, they consider drops as customer induced damage and automatically void your warranty with them. so if you have an asus, you almost gotta get squartrade to protect your investment. bestbuy has ADH too and their's isn't as cheap but may be more convenient since you would be right there to get it and i believe you have 30-days or maybe less to get it from them.