Apple has begun emailing past customers of its retail and online stores, notifying them of a special one-day Apple shopping event this Friday, November 26. According to the notice, Apple’s retail stores will open at 8:00 a.m. on Friday, while customers visiting the online store will have all day to place an order. In the past, Apple has offered modest sales on select products during such events; last year, it offered a discount of $101 on all…