I've never used the product mentioned.  However, I have used USB desktop wi-fi "antennas" such as Linksys WUSB54G and they work great, so there is no reason why an amplified external antenna wouldn't work.  I've heard of people making wi-fi antennas with "Pringles cans" that go 1/2 mile so a commercial product with better range is plausible.

Actually, the USB desktop devices are wi-fi card/antenna combo units (you don't need any other wi-fi equipment in/on the computer).  That's how they work.  The USB takes power and LAN signal from the computer, the wi-fi LAN adaptor is built into the "antenna".

>Have you personally tried this?  Seems like I will have to milk a few snakes
>to make it work?  I see no way of using a USB port as an antenna - just not
>even remotely the sale.