I think your best chance of getting it early will be to preorder it (which you've already done). I don't think any particular medthod of preorder will get it any faster than another. I preordered mine at my local GameStop on May,11th. Hopefully I will be one of the first to get it here. *fingers crossed*

Your best bet would be to go through EBgames, In stire pick up. My local one always seems to have there games in on time right when they open, or high profile games in earlier. My local Gamestop sucks, there never have anything early, and they always get there game deliveries in in the afternoon, and then take 3 hours to put it on the shelf because there lazy. Also if you live out towards the weastern part of the USA they tend to get there games in a day earlier for some reason I've noticed. Also definetly pre-order, most places only sell pre-orders early, so if you go in without a pre-order they'll turn you away. Unless your right there when they get there shipment in then ther're a good chance you could get it early. I wouldn't go through online sales either it usually takes longer in my opinion.