PDFtoMusic for Mac

From Myriad Software:

If you changed your score editor in the past, did you ever lose some music pieces you entered in the old one, because there was no easy way to convert them into a format that could be read by the new program? PDFtoMusic is tailored for you. Open a PDF document, and after a few seconds, you'll just have to click an icon to hear the score playing, and even the lyrics be sung. PDFtoMusic gives you full access at last to the huge PDF music score collection available on the Internet. If you wish to go further, with Melody Assistant or Harmony Assistant, you'll be able to alter the score, remove parts, transpose them, or completely rearrange the whole piece.