I just successfully generated a PDF document from the song set.  This means that soon, emailing the set will contain a PDF document that will retain the formatting found in OnSong.  I'm still working on getting the generated guitar tablature displaying, but otherwise it's all there including fonts, size and highlight colors.  I chose not to print the sticky notes in the PDF.

One thing to note with this update (when it becomes available), is that it changes the way font sizes are interpreted.  The original version of OnSong really didn't respect point size versus pixel size.  In order to normalize the print version and screen version, the font sizes had to be adapted to work better.  This means that when the update is installed, the fonts in your songs may be bigger than you want.  I think that's a small price to pay for being able to send PDFs.