VC-ClearCase is an Emacs package that adds ClearCase support to the standard VC version control functionality.
VC-ClearCase is available from SourceForge.
I no longer maintain VC-ClearCase, as Kevin Esler from Rational has written a replacement called "clearcase.el" and I am already using his replacement myself.
I will not be answering any email about VC-ClearCase or it’s replacement.