Best way to manage hundreds of materials?

I'm working on a game for iOS, and I need to make use of hundreds (probably 200 or so) of unique images. I've had them compressed down to 512x512 4bit PVRTC (so they're 128 kB).

I've created a generic scene that I can populate, and I've stuck all of the materials into a Resources folder.

Needless to say, it's a huge memory hog when I run it on a device (iPhone 3GS) and it's become a major headache/problem for me. Is there a better way (less memory-intensive) for me to go about doing this?

To be able to give you the best answer you should describe more precisely what you are trying to achieve. What are the 200 images? Are they symbols or textures. Why do you need 200? Do they need to be in 512 resolution? Are you making optimal use of the texture space? Maybe you can you combine several textures into one bigger texture.

If you target a pre-3GS the maximum texture size is 1024, after that it's 2048