Anti virus for Linux Server

Hi,

Any recommended anti virus for CentOS 5.5 64 bit ??

Try Clam AntiVirus (ClamAV), it is among the best anti virus for centos.

Does it support 64 bit Architecture and is it free ?
How exactly to manage it via Terminal ?

Yes it is Free open source software. But I am not sure about 64 bit support. You can check it from their FAQs

Even now I don’t think that it is neccesary to use AV on my linux desktop. These virii are mostly aimed at small servers. These are often badly looked after. So if they are infected, they can be used to spread spam, windows virii, etc.
However if linux continues to develop in favor of home users, security will suffer from it. Linux’s first lines of defence, the file permissions and root account, prevent the unauthorised spread of virii on your system. However these security systems are anything BUT friendly to a first-time linux user. If these were to disappear in the name of useability, Linux would suddenly become way more vulnerable. Ubuntu made the first step in ignoring the root account and relying upon sudo to handle permissions. Don’t get me wrong, I like Ubuntu but this is one of the few things I don’t like about it because it is a double-edged development.
For now I still feel safe enough to run AV-Free