About CXF plugin
CXF plugin has not been used in the latest eclipse.
How do I use the CXF in Eclipse?
The links below will give you some ideas. Step-by-step instructions are now available.
Whose using the plugin?
Currently, the CXF is only used by Eclipse STP project.
You can find more instructions in STP web site.
Also, here is a good tutorial tell you how to 'Use the Eclipse SOA Tools Platform plug-in to build and deploy a Web service'
NOTE: The tutorial is out of date, please use this page to get started with STP service creation.