Thanks guys.
Also, just to add to the AGF knowledge base, I talked to ASCAP yesterday and here is the process for publishing arrangements of Public Domain songs.
1. Set up a publishing ID with ASCAP. I did this years ago. There is a one time/lifetime fee (it wasn't much - I think it was around $100).
2. Let's say you are recording your arrangement of OH SUSANNA (written by Stephen Foster, but now Public Domain).
3. You would copyright your arrangement of OH SUSANNA (by sending a recording and/or written score of your arrangement - along with the appropriate paperwork and fee - to the U.S. Copyright Office).
See process here
4. Register your song with ASCAP. Just provide the name of the Public Domain song, who wrote it (if known), and let them know you have copyrighted an arrangement of the song.
Probably a similar process if you set up your publishing company with BMI instead of ASCAP