Just a warning they usually let people in 15-20 minutes before but (any store I have been to) does not let you check out until after opening. Something about the ancient technology they use takes a bit to go online and whatever. So yes you can shop early, but don't think you're getting in and out quickly. Think of it as early checkout queueing lol.
Update - No longer. Finally got around to looking it up. They had early entry for Executive and Business members, but it ended sometime around 2008. Some stores do open early, but it depends on the local management and is for everyone if/when they do it.