Always kind of wondered why my hot coffee that I let cool to room temperature and pour over ice doesn't have the same kind of flavor as the iced coffee I buy during the warmer months of the year. Since the weather is taking a turn for the warmer and it will soon be baking and pushing triple digits near my parts, I couldn't have been more pleased to discover that it is because ice coffee is apparently properly made by cold brewing it.
1) Combine ~4-5:1 water to coarsely ground coffee and stir to mix
2) Let sit 10+ hours (or overnight) in the fridge or just on the counter if you don't have room.`
3) Pour over a filter into your glass in the morning, with some ice and whatever else you like. You could use just a coffee filter, but something with larger pours is preferable so you don't lose all of the oils. I just use a metal strainer, but do end up with a small amount of grounds in my glass.
If you have a french press, that is the most elegant way to do all of this.
You can store this stuff in a pitcher for several days. Definitely gives that the taste that distinguished a properly brewed iced coffee from the hot variety, although mine seems a little weak on taste (might just be my coffee, which wasn't a great selection and I preground a month ago). I did read that this stuff supposedly is more concentrated than the hot brewed stuff, so be aware of that.
If you want to use ice, the other tip I picked up (and this is obvious) is to free coffee to make the ice so it doesn't get watered down.
edit: this stuff is definitely strong. I had my usual amount this morning (prob ~14 oz) and I'm definitely feeling it. I almost never feel the caffeine unless I drink a whole pot.