The official ABAP Programming Guidelines were presented at TechEd 2009 in Phoenix and were available at the conference book store:
Here is a glimpse of a typical chapter:
All in all, there are around 120 of such rules covering an area that spans from very general subjects like "Separation of Concerns" to very special subjects like "Usage of COLLECT for internal tables".
The rules are aimed at being reasonable but not dogmatic, profound but not fundamentalist. The compliance with these guidelines should be a given for a developer and not understood as a formalistic necessity.
Alltogether, they are more than just another collection of naming conventions ...