Installing Openfire on CentOS 5.5
The install process takes less than 15 minutes.

Do a basic install of CentOS with mySQL support and any other packages you want.
Installing Java:

If you don’t have Java install do the following:
Download Java from (java.com) and do the following:
mkdir /usr/java
cp jre-6u13-linux-i586-rpm.bin /usr/java
cd /usr/java
sh jre-6u13-linux-i586-rpm.bin
rpm -iv jre-6u13-linux-i586-rpm.bin

Installing Openfire 3.6.4:

(At the time of [...]