Open-With Manager lets you edit the list of file types a given application thinks it can open. This is most useful with regard to the Finder's "Open with" context menu; and it also affects the way applications behave when you drag files to their Dock symbols.
via manytricks.com
This is one of my favorite Mac utilities. I use Fluid to create a lot of SSBs, and I also have multiple Fusion VMs. The problem is they all like to impose upon the Finder Open With menu. No, I don't want to use my Gmail SSB to open an MP3 (though thanks for asking), and I don't want to open a Word document in Word 2010 or my XP VM.
Open-With Manager makes it very quick and easy to clean up the Open with menu. And there was much rejoicing.
Open-With Manager is free, but donations are appreciated.