You could try the DVD "Calling Coyotes Like the Pros"
It is a 2 DVD set and covers all the bases; rifles, calls, camo, set-up's, scouting.
Call the people at AllPredatorCalls.com and they will take care of you right. When you get the DVD there is an entire section on call selection and use. Watch that and then decide which style you prefer. Until you know how the different types are supposed to work and what looks good for your style, it is almost impossible to point you in the right direction.
For basic all around use you can start with 3 calls. A close range enticer, a medium range cottontail squeal, and a long range jack rabbit squeal. Even if you live in a part of the country that doesn't have jack rabbits the call seems to work real well and the tone seems to carry a good distance.