Download From
http://sourceforge.net/projects/rkhunter/
Install
tar zxvf rkhunter-*
cd rkhunter-*
./installer.sh --install
cd ..
rm -rf rkhunter*
Run /usr/local/bin/rkhunter --update to update the database
Run /usr/local/bin/rkhunter --propupd to create pre-required MD5 check sum
Run /usr/local/bin/rkhunter -c to run rkhunter
Review log file less /var/log/rkhunter.log
References:
http://sourceforge.net/projects/rkhunter/
http://www.howtoforge.com/faq/1_38_en.html