- Delete the Safari cache folder. This should be in ~/Library/Caches/Safari/.
- Create an empty text document and save it as 'Safari' (no extension) and place in ~/Library/Caches/. I think just about any type of Document would work for this, just make sure the name of the file matches the name of the old folder, this way, a new folder can't be created by Safari when one is needed
[robg adds: In the terminal, you can create this file quickly and easily by typing:
touch ~/Library/Caches/SafariI tested it a bit this morning, and it does indeed seem to work fine and prevent the caching of pages.]

