Architects are concerned with nothing less than the form of the physical environment and its effect on people's lives. Architecture is equal parts art and science, and it encompasses technical, social, aesthetic, and ethical concerns.
If you major in Architecture, your first year will be crucial. Freshman year will lay the foundation for the rest of your education, and it will be intense, to say the least. The focus of the first year is to train you to understand the conceptual, spatial, and abstract qualities of Architecture. You'll learn how to communicate ideas graphically through drawings and models, and how to assess and research architectural questions. You'll also learn a bit about architectural history and theory. You'll take some pretty heavy doses of math, too. Mostly, though, you'll spend tremendous amounts of time agonizing over minuscule details in studio - alone, in small groups, and one-on-one with faculty members (Architecture professors are some of the most dedicated around). You'll also observe more advanced students while they work.
If you make it through your daunting first year, you'll be well on your way to one of two degrees in Architecture. The Bachelor of Architecture requires a bare minimum of five years of study (expect to spend six). The Master of Architecture requires a minimum of three years of study following an unrelated bachelor's degree or two years following a four-year, pre-professional Architecture program. There are about 110 schools across the fruited plain that offer accredited professional programs in Architecture, and you need to graduate from one of these programs in order to become a licensed architect.
It can be pretty difficult to actually get into the school of Architecture at most universities, by the way. You'll need to submit a convincing portfolio of creative work and a personal statement.