Erik Barzeski found this hint and posted it on his blog. I have been using it for a few weeks now and thought that I would pass it along.
Basically if you create a ~/Library/Scripts/Applications/Finder folder, all of the scripts in the Finder folder will now appear at the top-level of the Script Menu when the Finder is the current application. Just add a folders containing scripts for each application, and the Script Menu will display the scripts for the current app.
[robg adds: If you read the comments in the blog entry, you'll see that some people had trouble making this work -- and I'd have to put myself on that list. I created a Finder folder in the right spot, but it just stayed at the bottom of the list (along with my other personal Scripts folders) even after restarting SystemUIServer. I haven't bothered trying a logout/login yet. Also note one comment regarding the Script menu needing to be rebuilt each time you switch apps. Still, this is potentially interesting...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20030402124522242