I have not found any, but if you find some good ones let me know. The standard SAS manuals on AF are just that manuals, not good books. I wish that I had some reading material when I started SAS/AF. I had to pester the other senior programmers in my organization for tips in SAS/AF.
My advice is first learn the object programming model and how they relate to each other. (In short SAS tried to copy the VB type of environment. Having used both envs, they didn't come close. There are so many window limitations in the SAS module.)
There are sample programs on the SAS website.
I hope that this helped you,
Klaz