I made orange syrup recently, and it turned out pretty good. My way is somewhat different, less fancy, and much simpler than sneff's super fancy way. It works well on french toast and waffles, and less well on pancakes, and makes an awesome addition to lemonade, or a substitute to the sugar. Without further ado, I present you with:

Delta-Sys's recipe of orange syrup:

1/2 Cup of white sugar
3/4 cup of pulp-less orange juice
zest of one orange
about 2 tablespoons of lemon juice

Put everything in a pot, mix a little, turn on low heat and don't touch it. When everything is dissolved, skim the scuz from the top, and keep it over very low heat for another 3 or 4 minutes. Take it off, straining the zest, if you care to, and refrigerate. It gets thicker as it cools.