- Go to System -> Library -> CoreServices -> loginwindow.app -> Contents -> Resources -> your_language.lproj, where your_language is English, German, etc.
- Copy ProcessPanel.nib from this folder to the Desktop
- Open it in Interface Builder
- In Process Builder, select 'About this Mac' under 'Instances'
- Select Tools -> Info in the menu
- You get a mask where you can change the window title
- Close and save your changes
- Start from another volume and replace the original file with the changed one. Don't forget to backup the original file!
- Once you get back to the original system, you may want to set the privileges correctly (read & write: system, write: wheel and others). I don't know if this really matters but it's more elegant to do so.
[Editor's note: I have not tested this one myself...]

