This is home of vim plugin http://www.vim.org/scripts/script.php?script_id=1888
If you are editing diff file and you want to jump quickly to corresponding source files, function DiffGoFile does that. Place cursor on the spot in diff file which interests you, call |DiffGoFile| and you will be presented with the source file exactly at the place you were looking at. Currently only unified diff is supported, but the script has framework for adding more types.