How to truss a chicken?
Thomas Keller's Ad Hoc Cookbook (one of the best cookbooks I've seen) recommends the following:


Place the chicken with the legs towards you.  Tuck the wing tips under the bird.  Cut a piece of chicken twine about 3 feet long and center it under the neck of the breast.  Pull the twine up over the breast towards you.
Knot the twine, pulling it tight to plump the breast.
Bring the ends of the twine around the ends of the drumsticks and straight up.
Tie as before to pull the ends of the drumsticks together and form a compatct bird.  Then tie again to secure the knot.