# httpd -t
[Fri Jun 08 11:12:19 2012] [warn] module ssl_module is already loaded, skipping
Syntax OK

This happens, because ssl module is enabled in more than 1 place:

# grep ssl_module -rI /etc/httpd/*
conf/httpd.conf:LoadModule ssl_module /usr/lib64/httpd/modules/mod_ssl.so
conf.d/ssl.conf:LoadModule ssl_module modules/mod_ssl.so

we load all needed modules in one place – /etc/httpd/conf/httpd.conf.
So we can safely comment out in /etc/httpd/conf.d/ssl.conf file.

edit /etc/httpd/conf.d/ssl.conf file
and comment out this line:

#LoadModule ssl_module modules/mod_ssl.so

save file, and problem fixed:

# httpd -t
Syntax OK