Questions about the safety of drinking sun tea make the substitution of refrigerator tea a good idea. I always brew my tea with boiling water, but have drank sun tea on occasion, despite my biology background causing me to balk a bit. Now I'll be even more diligent with handling tea bags and brewed tea.
Here is a recipe for refrigerator tea from frugalliving.com:

REFRIGERATOR TEA

INGREDIENTS:
* 6-8 tea bags (use more or less according to taste)
* 2 quarts water

PREPARATION:
1. Fill a two-quart pitcher with cold water.
2. Add in your tea bags.
3. Steep in the refrigerator overnight.
4. Sweeten with sugar (if desired), and serve.

Serving ideas:
* Garnish with slices of citrus fruit, berries, fresh mint or edible flowers
* Flavor with fruit juice for a more exotic taste
* Fill an ice cube tray with tea, and freeze to create ice cubes that won't water down your drink.

What a shame we have to put so much into keeping our food from making us sick.