What is a good technique to make Iced Tea?
The general method for iced tea is to boil water, and use double the tea for the amount of water and steep it for twice as long. Once steeped, add an equal amount of ice, and the ice will water down the tea as it melts and cools it down. If you want to sweeten with sugar, do it while the tea is hot.

This is the fast method, as you'll have iced tea as quickly as you can cool it (an hour or so in the fridge).

Alternately, you can steep the tea overnight in cold water in the fridge, using a normal tea:water ratio. This is the slow way. :-) If you want to sweeten the tea, make a simple syrup and add it (sugar won't dissolve very well in cold water).

Whether you use loose leaf or bags is really up to you. Tea purists will always say that loose leaf is better, but bags will work fine if you don't have a refined tea palette. Fruity teas often make really good iced tea, even if you're not a fan of fruity hot tea.