How to change "__MyCompanyName__" ?

24/09/03 11:07
Open the ProjectBuilder preferences file (~/Library/Preferences/com.apple.ProjectBuilder.plist) or the Xcode one (~/Library/Preferences/com.apple.Xcode.plist) and edit the dictionary associated with the key PBXCustomTemplateMacroDefinitions (create one if it does not exist, as child of the root node), edit or add the key ORGANIZATIONNAME, the associated string value will be used when PB creates new source files.

You could also do it via Terminal.app:
defaults write com.apple.ProjectBuilder PBXCustomTemplateMacroDefinitions '{ "ORGANIZATIONNAME" = "My Company";}'
or
defaults write com.apple.Xcode PBXCustomTemplateMacroDefinitions '{ "ORGANIZATIONNAME" = "My Company";}'

Authored by: Anonymous on Sunday, October 26 2003 @ 11:00 PM GMT
I am sorry but I don't understand this. or it does not work.

What do you mean by "the dictionary associated with the
PBXCustomTemplateMacroDefinitions"? Is that the dictionary
that contains that very key? I cannot find that key, so how am I
supposed to know which dict it should be in?

"create one if it does not exist"... you mean create a dict or a
key? and by what name?

and lastly: are you sure it's "ORGANIZATIONNAME" and not
"ORGANISATIONNAME"?