Pathway "Gene-Swapper" Utility for PathVisio - available for download
Justin Preece and Mamatha Hanumappa have written a Perl utility application designed to map homologous genes from one species onto the PathVisio pathway diagram of another species. Requires only a GPML PathVisio document, a CSV file of homolog mappings, and a configuration file.
The source code and documentation may be found here.
Further enhancements and/or a collaboration with the PathVisio group on a plug-in version are likely forthcoming.