To see if it's running:
netstat -an | grep :23
If there is a line with yourip:23 in a LISTEN state, then it's running. It probably isn't since it's insecure and ssh is preferred.
To get it running, first make sure it's installed:
rpm -q telnet
if not install the RPM from your Madrake media/repository.
Then make sure it's enabled:
chkconfig --list telnet
if it isn't, enable it:
chkconfig telnet on