It varies depending on your vehicle but can be accomplished on most vehicles with simple hand tools. Once your have removed the tire the caliper can be removed by loosening two bolts that hold it on. The pads will then come out and you can pull off the rotor.
It's definitely doable on your own. You'll probably need a socket set and clamps, and a jack. Do one tire at a time and be careful with the brake lines.
Brake rotors and pads a quite simple to replace. It is usually only 2 bolts that hold on the caliper to replace the pads. And only about 2 or 3 more to remove the caliper bracket to replace the rotor.