This is driving me mad!

I have the body tag set to 100%, a container div set to 100% height, and then there was divs within that which all need to be 100% height, but IE, firefox and Opera interpret it all differently!!!!!!!!!!!!!!!!
The body is not 100% height in Firefox no matter what I type in, and Opera and IE both do what I want, but not at the same time!

Are there any links that anyone knows of to good tutorials or information about this problem?

Alternatively if anyone knows a solution based on what I've said I'd love to hear the answer!