Warbike, a work by David McCallum currently featuring in Sound Cycles and Mobile City at Interaccess, Electronic Media Arts Centre in Toronto, is a mobile reception unit for wireless networks which transforms the:

wireless network activity into sound. As you cycle the streets, you’ll hear the activity of this invisible communications layer that permeates our public spaces.

David’s thesis about the Warbike (which includes some interesting references to works I have not seen before) on his website is worth a look.

Originally seen on the Sonic Arts Network mailing list, Sanlist.