When sending a pitch to a national public radio show you can do it electronically or you can do it on paper.

We do most of our pitching with paper, simply because we publish books, and when we send out a physical book-a hard copy of a book-we just slip in the paper press kit with it. We do not usually just send out a press release because really that only skims the surface. We normally would also include a one-page bio of the expert, the author. We would include a Q&A with the author, one where we've sort of provided them with the questions, and they've written the five- to seven-sentence answer for us. We would include any reviews that the book has received thus far that sort of helps support our claim that the book is important, or the book is well-written. We put all of that together. Usually we will get a plain, blank folder that you get at Staples, and other times it is a fancy print folder. We will put all of that information in there, and send it via mail.

There is a lot more great information where this came from and you can find it in the Audio Transcript, How to Get Booked on National Public Radio.
http://101publicrelations.com/nationalpublicradio.html?utm_source=prideas&utm_content=npr