Fast diff command for large files?

[Kirk Strauser]

I need to routinely find the diffs between two multigigabyte text files 
(exporting a set of FoxPro tables to a PostgreSQL database without doing a 
complete dump/reload each time, in case you were wondering).  GNU diff from 
the base system and from ports chokes.  The textproc/2bsd-diff works OK, 
but is glacially slow.

I'm basically looking for something that generates easily-parseable text.  
Since this is a young project, I don't particularly care if the output 
format is different from diff's.  Any suggestions?
-- 
Kirk Strauser