Apple typically spans about two and a half weeks from new iPhone announcement to release date, so expect Friday October 21st as the most likely on-sale target. If there’s sufficient initial inventory to allow it, online preorders will begin about a week before that date, but may be cut off quickly if demand proves to be so high that the preorders risk cutting into retail launch day inventory. Then on the 21st (or the night before, if Apple opts for an early morning launch), lines will form at retailers ranging from Apple Stores and carrier stores to electronics stores like Radio Shack and Best Buy, and we’ll soon find out just how much iPhone 5 inventory Apple really has on hand.