Start using a good text editor with an advanced search (and replace is always nice) functionality. Homesite is what I use, but that's just from years and years of preference (been using it since long before it was even owned by Allaire, much less Macromedia).
Then when things like this come up, you just point your handy dandy text editor to look through ALL your Photopost files (templates, php, config, css, everything) for a variable or string or whatever and it will do the work for you. No need to kill minutes, much less hours, doing it by hand.
Been there, done that, and it ain't no fun!