We have done a lot of online research and have talked with neighbors who have installed cisterns. One home has one 500 gallon buried tank; one home has three cisterns - two above-ground, one buried; one home has two cisterns on metal stands. You need to talk to folks that have cisterns and to do your own research to find what might be right for you/your situation. Here's some good online sources of information:
DIY Water Projects
Building a High Pressured Solar Powered Rainwater Irrigation System
Rainwater Harvesting Systems
We have looked at several different cistern scenarios, including burying a large tank (500 gallons or more), which some of the folks in our subdivision have successfully done. We have decided that, for us, the best scenario right now is an above-ground tank. The tank will go under the deck on an existing cement pad:
This is, essentially, an experiment for us. We are taking steps to conserve our indoor water and to provide water for outdoor purposes, trying to be responsibly members of planet Earth. We may well install another cistern later this year or next year if we decide one cistern is not enough to meet our needs.
Be responsible members of planet Earth, little ones, and reduce, reuse, recycle, repurpose, and conserve any and every way you can.
UPDATE (9/26/14): The cistern was delivered this week, finally! We aren't sure if we'll get it fully installed before winter, but we will have it up and running by next spring for sure.