Some of your learning options include flight schools, independent flight instruction, and colleges. I'll cover them in greater detail in a moment. First, consider where you want flying to take you. If you've already made up your mind that you want to be a commercial pilot, and a private pilot certificate is just your first step, consider one of the colleges or larger flight schools designed to train professional aviators. Why? Not only will you learn more about commercial aviation, your diploma will be more acceptable to a major airline than if you take training from an independent flight instructor at Podunk Field. In addition, scholarships are available for many of the formal training institutions, some of them paid by commercial airlines that would like you to come to work for them after graduation.
The majority of new pilots — especially those who already have non-aviation careers — opt to take less formal instruction, in which case Podunk Field is just fine. In fact, they will be flying in and out of Podunk Field for the foreseeable future, so why not start there? It's handy to home and work. Or if there's a well-known flight school within driving distance, new pilots might enroll there to take advantage of the opportunity to fly more frequently.
Also, consider one of the accelerated private-pilot courses available may places across the U.S. Within a few weeks of concentrated work you may be able to walk away with a pilot certificate. Alternately, consider training as a sport pilot (lower time requirements and costs), then upgrading to a private pilot certificate. The point here is that the type of training you select depends on what your long-term flying goals are. If you really don't have any, a local flight school or independent flight instructor is as good a place as any to start.
Ground school is classroom training in preparation for flight. The flight instruction method you select will often dictate the ground school you use. For example, Cessna Flight Schools use their own training package and the ground school materials come with it. Independent flight instructors often have a ground-school package of their own, have a preference for which ground school you use, or are willing to make some recommendations and leave the final decision up to you.