Short howto on installing NTOP on CentOS.  I'll rewrite this with compiling it as a rpm later.

mkdir /tmp/ntop
cd /tmp/ntop
yum install -y gdbm-devel libpcap-devel zlib-devel rrdtool-devel subversion \
libtool automake autoconf make
svn co https://svn.ntop.org/svn/ntop/trunk/ntop
cd /tmp/ntop/ntop
./autogen.sh
make;make install;make install-data-as
useradd ntop;chown -R ntop:ntop /usr/local/share/ntop
mkdir /usr/local/var/ntop/rrd
mkdir /usr/local/var/ntop;mkdir /usr/local/var/ntop/rrd/graphics
mkdir /usr/local/var/ntop/rrd/interfaces;mkdir /usr/local/var/ntop/rrd/flows
chown -R nobody:nobody /usr/local/var/ntop

Should be about it.