This is super easy to do. I did it myself 2 summers ago. The shape of my yard was annoying for manual watering.
Go to this website and map out your yard. they will email you a plan for you to follow. Its over kill but basically gives you an idea what to do.
http://www.orbitirrigation.com/
The hardest part may be digging the trench for the lines. The pros have a pushing tool. If you dig you only have to dig a 4" wide trench 8" or so deep.
You need a seperate water line to the outside of your house, put a check valve on it inside the house and a shut off valve as well. The water line from the house runs into these valves/manafold, which open and close and allows for watering the zone. Run a line from the valve to each zone you want watered and attach the sprinkler head x feet apart. 4-8 heads per line/zone dependent on pressure. Hook up the timer with a rain sensor and you are golden.
Smile every morning when you get in your car for work having done your watering while you were eating your cereal.