Install RPM For CentOS 6.X
32-BIT
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.i686.rpm
rpm -Uhv rpmforge-release*.rf.i386.rpm
64BIT
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm
rpm -Uhv rpmforge-release*.rf.x86_64.rpm
Install Htop In CentOS Using YUM
yum install htop