Online shop that aggregates other shops?

[txrandom]

My uncle has some friends that sell various products. He wants to sell them all on his site, but instead of holding inventory, just automatically make an order with each of his friend's site whenever a customer orders from my uncle's site. I told him this would be pretty hard to do since something would have to be made to automatically order from each of his friend's sites. Anyone know of something like this?

 

[olds]

Ask amazon.com

 

[txrandom]

Amazon holds their own inventory, which doesn't include stuff my uncle wants to sell.