The assumption that something "is running" is wrong. When started, Shorewall only loads and enables firewall rules, and then the kernel netfilter code does the rest. A good installation of Shorewall would provide a service script, which would give status output and which you can query and use like this:
chkconfig shorewall --list
to enable/disable it for next reboot or run-level change.
service shorewall start
service shorewall stop
See "service --help" and "man chkconfig".
There's a Shorewall package in
http://fedora.us and
http://fedoraproject.org/pre-extras/3/i386/