For example on CentOS (based on RedHat), htop package is not in default repositories.

One need to isntall EPEL (Extra Packages for Enterprise Linux)
Example tutorial: http://www.rackspace.com/knowledge_c...os-and-red-hat
or google "how to install epel"

On CentOS 5.x 64 bit i installed like this:
Code:
wget http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el5.rf.x86_64.rpmrpm -Uvh rpmforge-release-0.5.3-1.el5.rf.x86_64.rpm
yum install htop -y
then open htop by "htop" command