You don't need a license to listen to shortwave, you only need a
liscense to transmit as an amateur radio operator. A good entry-level
reciever is a Kaito KA-1101.
(http://www.surpluscomputers.com/stor...&item=CES10486)
No SSB, though, so broadcast signals only. One interference issue is
Broadband over Power Lines, which makes a huge amount of noise over the
entire shortwave spectrum.