I'm a big fan of National Public Radio and the program All Songs Considered. Vermont Public Radio has it's own version called My Place, hosted by Joel Nashman, and is an incredibly detailed look at music history and musicians, which is always fun to listen to.
In recent weeks, NPR has put up a couple of really good concerts online:
Josh Ritter - Listen
José González - Listen
Iron & Wine - Listen
Rilo Kiley - Listen