That was easy to figure out...it's a recording of the vocal version (NOT meaning that Batgirl sings it, of course!) of the Batgirl theme from the Batman tv series from the 60's. There were a couple of the early episodes with Batgirl, who was introduced in the show's third season, where you actually get to hear a song about Batgirl as she's riding along on her Batgirl cycle. Check out a video of the song here:

http://www.youtube.com/watch?v=aX5zNM_KA8I

Billy May composed the music and Willy Mack wrote the lyrics.
I think it's actually been included as a bonus track on a reissue of the tv series soundtrack album.

kriegerg69, July 31, 2012; 9:22 PM