grenadine syrup

method 1:

Pour two cups of pomegranate juice (not pomegranate juice cocktail) into a saucepan. Bring to a boil, then simmer over medium-low heat until reduced by half. Add one cup of sugar, and stir until dissolved. Remove from heat and let cool; if desired, add high-proof vodka or grain alcohol as a preservative (it also keeps well, and doesn’t freeze solid, in a plastic container in the freezer).

from Killer Cocktails by David Wondrich

method 2:

Take one cup of pomegranate juice, and place it in a jar with one cup of granulated sugar. Seal tightly and shake like hell until all of the sugar is dissolved. Add another ounce or two of sugar and repeat. Voila - a simple grenadine. [Optional: Add an ounce of high-proof vodka or grain alcohol as a preservative. You can also store this in a plastic container in the freezer; the high volume of sugar keeps it from freezing, and you can just tip out a little frigid syrup each time you need it.] Add food red food coloring if desired.

from cocktailchronicles.com - at least, thats the last post i can find on the trail, lol.

method 3:

2.25 lbs pomegranates
1 pint water
sugar (see instructions)
red food coloring (optional)

Separate the pomegranate seeds from the membranes and skin. In a heavy saucepan, cover pomegranate seeds with 1 pint of water and simmer, stirring until juice sacs release their juice, about 5 minutes. Pour through a cheesecloth-layered sieve into a bowl, pressing the juice from the seeds. Discard seeds.

Measure the strained pomegranate juice and add an equal amount of sugar. Pour into saucepan and bring to a boil. Reduce heat and simmer for 10 to 15 minutes. Cool to room temperature. Add food coloring, if using. Pour into a decorative stoppered bottle.

taken from peggy filippone at about.com