At the base of the bird's breast you make the cut.
Feel for where the breast bone stops and the stomach muscle starts. This is the soft area that a small cut can be made but not too deep. I slice from the base of the breast bone just short of the annus. Don't cut into the vital area but just slice the skin. You shold be able to pinch this skin and it will help you on how deep to cut.
Innards can be then pulled out with very little mess.
As stated before as I forgot to add it....I do carry ice packs that if it is hot I shove into the cavity to cool the bird quickly.
this is how I clean a turkey and I usually do this quickly if I do not need to register the bird. If i do I do gut it after registration or do this as I don't have to gut it.
http://forum.hunting.net/asppg/tm.asp?m=579399
JW!