Here in The
you can't order by phone, mail or web, but the situation on the other side of the big herringpond is probably much different. But from what I gather here on this forum it is unlikely someone collects your order and that you pick it up.
It's usual that the customer, you in this case, collects all boxes at the warehouse, information where to find it in the warehouse is in the showroom (sometimes at computerstations in the warehouse too). Only some kitchenitems or couches has to be ordered.
Information about stock you find on Ikeas webiste, but this is not always reliable.