There is a group online called webSDR that has several HF SDR (software-defined radio) around the world. You are able to listen and control what frequencies you listen to. It's really kind of neat to play with and is free!

• NA5B - Washington DC Area SDR HF (mobile)
• N4BUT - WebSDR receiver located in Orlando, Florida (mobile)
• K3FEF WebSDR in NE Pennsylvania (mobile)
• Northern Utah WebSDR
• KFS WebSDR in San Fransico, CA (mobile)