With Wyeast smack packs, the idea is to smack the pack to release the mini wort in there, and to "revive" the yeast. This usually takes somewhere roughly in the vicinity of 12-24 hours, but mileage varies alot. The package will puff up like a balloon.
At that point, you either pitch it directly, or, as most people here do, make a starter with a small amount (maybe a pint or a quart) of about 1.040 wort. Ideally, pitch the starter when it is at high kreusen. If you're not ready to pitch then, you can refridgerate it and warm it back to room temp before you pitch it.
