I don't have any experience myself in breeding boas but I plan to in a few years and have already looked around for different sources of info for boa breeding.
What seems to be a good choice and definitely one I will invest in is Jeff Ronne's Boa Breeding video. A very well reputed long standing and successful boa breeder, the video seems to be a very worthwhile investment.
http://www.boaphile.com
I also plan on obtaining books but haven't researched all that much into good titles yet.
Breeding boas seem to be much trickier than most other species and there are many ways to go about it apparently. I look forward to that challenge one day!
Pixie