i agree with jawdub.
don't waste your money on the "live sand" they sell in bags. the dry sand will become live soon enough.
you can start the cycle with a piece of raw shrimp if you like.
personally, i'd leave the sand out for now. add my live rock, cure it..vacuum out all the nastys that will fall off of it onto the tank botom, and THEN add my dead sand. it will be live before you know it.
a good question for you-
how deep of a sand bed are you talking about?
if it's only 1 or 2 inches for aesthetics, then don't bother worrying about it coming live. you are not going to get any filtration benefits from it being that shallow anyway.
if you are considering a DSB, then it should be 4" or more, and i would still buy a cup of sand from a local reefer rather than purchase that bag-live stuff.
it's a common misconception that that sand is full of critters too. it's only got a small amount of bacteria in it. no pods or anything like that. you can add your own bacteria easily and cheaply.