Many have posted of their trials and tribulations in attempting to obtain their card. We listened, and we learned. A week or so before Tom's birthday we went to INM (Immigration) and applied for Tom's CURP -
Immigration (INM) office is at the corner of Ave. Colon and calle 6, Colonia Garcia Gineres 999-928-5832 or 999-928-6141
EDIT * Thanks to Leslie Limon for the acronym identification - CURP stands for Clave Unico de Registro Publico.
We had all the paperwork and copies that so many learned were needed, the hard way.
Complete copies of ALL pages of both FM3 and Passport, comprobante de domicilo, and the completed form requesting the CURP.
Within a week we had the CURP.
* EDIT - and according to MCM - You can also get your CURP at Registro Civil de Estado (Calle 65 between 64 y 66, she thinks). Just bring your FM-3, no copies, no passport.
Then this morning we headed out to get Tom's identification photo. Getting the photo took us about 35 minutes. At Wal-Mart on Montejo and Perez Ponce just as you enter the front door on the right is the photo area, you ask for photos de identificacion, tamaño infantil, color. You get about 6 postage stamp size photos for 30mxp.
Thusly armed we were off to the local office of the Instituto Nacional de las Personas Adultas Mayores (National Institute for Senior Citizens, or INAPAM) office at:
59 x Av. Itzaes y 90, Modulo 2, 999-923-9600
where along with his new photo, a copy of first 2 information pages of FM3 and ORIGINAL FM3, and a copy of the comprobante de domicilo, we approached the INAPAM door, as I placed my hand on the doorknob, the young woman sitting at the plastic table asked if she could help us. 
I thought she was just waiting like several others already there. Turns out she has the paperwork for the INAPAM card. We explained what we wanted, showed her the documents, she asked to see Tom's passport which we didn't have with us, doh! Then said we didn't have the CURP number, I turned to the correct page pointed it out to her, she wrote our address on the back of the FM3 copy, asked for emergency contact - ME! and my cell phone nuber, then Tom's cellphone. She took the copy, and the photo and told us to wait as she entered the room.
We waited, and waited, and waited, and waited, and after about 15 minutes a woman opens the door, looks at us and motions to us, well actually she only wanted Tom, to follow. I was asked to wait outside. This was a little disconcerting and I could see the brief look of panic on Tom's face; he doesn't speak much spanish just yet.
About 4 minutes pass and Tom comes out with his new INAPAM card, and a booklet identifying possible discounts
SUCCESS
We celebrated by going out for lunch, nope, not at any of the places where we could have received a discount, there's always tomorrow!