I also have my own sprinkler system. What is this digging of trenches you guys are referring to? F-that man, I rented a ditch with, and let that bad boy do all the work.
I used the RainBird Sprinkler design service. It worked great. Of course when we decided to build the deck, I had to move a couple of zones in the back yard, but what the heck. I also used the flexible poly pipe instead of pvc, just my preference. The pvc works just as well.
http://www.rainbird.com/diy/design/index.htm
Don't be intimidated by this project. You can do it yourself and save lots of $$, that can then, be spent on the Porsche.
Bill