It turns out that there is no libapache2-mod-fcgi package in Debian (woody, sarge, sid, experimental).
This seems to be because of the following phrase in the LICENSE.TERMS of mod_fastcgi which is in conflict with the Debian Free Software Guidelines Debian Social Contract Paragraph 3 and 6:
Open Market permits you to use, copy, modify, distribute, and license
this Software and the Documentation
-> solely for the purpose of implementing the FastCGI specification <-