[Off topic] Need help understanding DSL

[Simon Campbell <simtrader@xxxxxxxxxx>]

Please excuse the novice-speak here:

ADSL has just come to my neck of the woods and the ISP can provide a modem 
for either a network ethernet card, or a USB port.  Since I have neither on 
my machine, I need to decide which of these cards I should purchase to 
stick in a PCI slot.

The question is: which card should I buy - USB or Ethernet? (exact model 
suggestions appreciated!).  I use a stand-alone PC and only want to use the 
phone at the same time as be on the internet.

The ISP also is selling "ADSL Routers" - do I need one?!

Thanks in advance,
Simon.