John: please check your state regulations concerning the wire size, length of run et c. Regulations can change from state to state but all must follow Federal regs. The advice as to the type and size of breaker is correct AFAIK. The type and size of the wiring must be figured for the installation (usually). Here in Md. almost all residences are wired "split-phase" meaning that the incoming service consists of 240 volts split between the "ground". In the main distribution box, one side of the main versus "ground" is distributed on one column of breakers (120 volt each) and the other side to the opposite side. The box is designed so that a single pole breaker will give 120 volts to ground which ever side it is connected. A double pole breaker will span the two "hot" sides to produce a 240 volt connection.

There is no reason that you cannot do this yourself with the proper precautions and reliable hardware. All breakers are not equal. Don't skimp here. Get the best available and be sure it is in code.