How To Preserve Fresh Herbs:
The faster the herbs dry, the more flavorful the resulting dried herb will be.
Conventional Oven: Place clean dry herb sprigs on a foil-lined baking sheet. Bake at the lowest setting until herbs are dry and brittle. This should take about 12 hours. Strip leaves from stems & place in small airtight storage containers.
Air Drying: Tie small bunches of herbs with string and hang upside down by the stems in a dry warm spot out of direct sunlight. Be sure air circulates freely around the bunches. Let dry till leaves are brittle. This usually takes a few days to a week, depending on the thickness of the leaves. Pick off the dried leaves & store in tightly covered containers in a cool, dry place about two weeks or till dry and brittle.
Microwave Drying: Pick when the dew has just gone off. Put on paper towels on a plate in the microwave. Zap on high for a minute to start (at that point they appear "wet"). Stir them, zap again for another minute, move around again, and zap approximately 30 seconds more or until they are dry and crumbly. Rub between your hands to break up, pick out any twiggy parts and put in small jars or baggies.
Freezing Herbs: Wrap in foil or plastic wrap. You can also chop clean herbs, place in ice cube trays & fill with water. When needed remove herb ice cubes and drop into hot cooking liquid. You can also wrap bunches of fresh herbs in foil or plastic wrap and freeze them for several weeks. You should expect some discoloration of frozen herbs. Mark the date on the container of your dried herbs. They can be kept for one year. Heat, moisture and light rob herbs of flavor. You can also make herb butters and herb vinegars.
Handling and Storage of Herbs and Spices:
Whole spices will keep their flavor indefinitely as long as they are kept in tightly closed containers away from heat and light. Herbs in leaf form will keep longer than herbs in ground form. Ground spices and herbs will keep their flavor for up to a year after purchase (whether opened or unopened, as long as they were fresh when purchased and kept in tightly closed containers in a cool place. If kept at room temperature, in a pantry for example, herbs and spices will keep for only 6 months.
Never store herbs and spices next to or above the stove (this will shorten their life). To tell if a herb or a spice has lost its flavor, smell it - if it has no aroma, it should be discarded.
Taken from: Hhttp://whatscookingamerica.net/herbs.htm