Rick,
please be more specific about your requirements.
Text/HTML uses DotNetNuke.Services.TokenReplace, to replace tokens in the text and does not create its own tokens for internal use
Announcements 4 is a WAP module, you need to install source code to edit and VS 2005/2008 Standard, Pro or Team version to compile. This module creates its own tokenreplace class to be able to use internal tokens for skinning.
If you plan to extend token replace for general use (by all modules and Skin objects), you need to extend core token replace, which requires modifications in the framework, which is not recommended.