There's usually two types of launches. Hard and paper.
In a hard launch, on the date that the company says that product will be released, resellers and stores already have that product ready to sell on THAT day.
Like Ownage said, a paper launch is the opposite. It's when that company announces that product is released, gives out specs and information on paper and consumers have to wait as the company ships out the product to resellers and stores.
also with paper launches, there is a quantity problem in the beginning, as that the first cards are just being finished manufactured. So there is a limited quantity. Conroe will be a hard launch, as there are already people selling it.