The MacApper weblog details how to clean out Finder's Open With menu so that uninstalled and duplicate applications don't bog down the list of apps you want to use.
- Go to your Home/Library/Preferences folder
- Find "com.apple.LaunchServices" file and trash it (you can back it up if you want)
- Test it out!
The list is generated by your Mac based on programs you install, but it doesn't update that regularly, so if you try out a lot of applications on you Mac, this list can get pretty bloated with apps you no longer need. If that describes you, MacApper's simple steps should do the trick. If you want to get even more granular with your Open With Menu, check out the Mac OS X Hints post below.