FZip is an Actionscript 3 class library to load standard
ZIP archives and extract/decompress contained files.
FZip parses ZIP archives progressively, allowing access
to contained files while the archive is loading.
The potential for this is impressive, and they've already implimented it in ways I wouldn't've thought possible - an automatic .air file update checker. I'm not even sure there is a file format left that the ActionScript 3 trio can't manipulate...