NPR, formerly National Public Radio, is a privately and publicly funded non-profit membership media organization that serves as a national syndicator to a network of 900 public radio stations in the United States. (Read more about it.)
How can I find it online?
The main site is www.npr.org. This is where you can choose the topic and program you wish to listen to.
Are there any related mobile applications?
Yes, plenty! Have a look at www.npr.org/services/mobile