CAP is a VERY good starting point, as we are all updating each other with the pros and cons of individual affiliate programs. There are other good sources but I do enjoy the friendliness and open spirit here at CAP.
Once you start doing some numbers, a number of the program managers will contact you and try to work with you more closely.
If you really want a good educational experience make sure you attend one of the Casino Affiliate Conventions (CAC), next one is in Vegas in September. Good place to meet everyone and see what’s what.