Online and in stores (According to phone scoop.) Package doesn't include a usb cable so you'll have to purchase that seperate (About $20.) You can get an 8GB memory card as well (I believe it's $60-65.) You can by these accessories online via a 3rd party but I would be careful when it comes to purchasing a "Less expensive" memory card as I have had many issues with some of them with my prior phones.

Also, on the premier site it appears as if the rebate card link isn't available so I am assuming you can just go to the At&t site and just print it from there. Don't forget to leave some feedback, I normally wait a month before purchasing a new phone because of possible bugs with the first edition.