I've been searching around and haven't found any reference to tools that can create Safari's webarchive format.
Does anyone have pointers to code for creating this format, or at least a format reference documentation?
Ideally I'd like to build a tool that takes a directory and splits out a webarchive, for loading into a iPhone.
To expand on what Ben said: CFLite (the cross-platform open-source subset of Core Foundation) ships with a plist parser. If you can link against that, it should be quite simple to work with .webarchive files, which are simply property lists that concatenate all files (HTML, CSS, etc.) into one.
There are other libraries as well, such as Mac-PropertyList on CPAN for Perl.