I first learned this method last summer and we were able to use fresh cilantro and basil all winter! Some herbs are best used fresh, such as cilantro. When dried, it loses all it's flavor. Of course, fresh basil can be used to make pesto all winter! I'm thinking you could do most any fresh herb this way. Perhaps I'll also try chives this season to use in potato dishes all winter.
The herbs will be soggy, so they'll have to be used in a processed dish (such as salsa or pesto) rather than as a garnish or something that requires them to be fresh and perky.
To preserve them for winter, simply freeze them in ice cube trays then when frozen you'll remove the cubes and put them all in a freezer bag.
Here are some pictures of my recent cilantro harvest (they seeded all over my garden from last year's composted seeded plants).
First, harvest and wash.
Then remove the leaves and stuff them into the ice cube trays.
Last, fill the tray with water and place in the freezer. When they're frozen, pop the cubes out of the tray and into a large freezer bag. In the winter, take some out and let them thaw in a bowl of hot water. Then use as you would when fresh.
Now, later in the summer I will use this frozen cilantro to make and can Salsa Verde!