Is there any Free Corporate AntiVirus Software out there.

I don't think there are any free versions for the corporate environment.  You could get always get a 30 day demo and then see if you like the product and then make a decision off that.  Or even test several products till you find one you are content with.  

There are some open source anti virus solutions, but I don't see why you should rely on free (or in other words absolutely zero support) on something as important as virus protection.

http://www.clamwin.com/
http://www.openantivirus.org/projects.php

And here's an open source FireWall  (but you'll need to run it in on a Linux box - most commercial firewalls do anyway)

http://www.smoothwall.org/

And an open source IDS/IPS (ideally should run on a *NIX box as well - but is fully compatible with Windows)

http://www.snort.org/

I still don't suggest rellying too much on open source. Although there is good community support, nothing beats a paid service. And I think security is something that you should not compromize on.

Why not save some money and use OpenOffice instead of MS Office? And use that money on your IT security needs (just a thought).

Hope that helps!

The major draw back for ClamWin is that it does not have real time scanning yet (it does however scan emails in real time), but it's in the works, and thus will be fully compatibly with Windows Security Centre in the near future.

Hey it's open source, what can you expect?

Hope that helps!

Open source is what i am looking for. its not really a main line of defense but more or less the second line.
Right now i am searching for a good enterprise/Corp antivirus that is inexpensive and it works well.

I have tried Symantec. did not like it.
I have tried Sophos.  did not like it.

However it seems that Avast! detects more and finds more then both of those two combine.

Any other suggestions?

Avast is very good

also f-secure

http://www.f-secure.com/products/fsavcsu.html

>> Open source is what i am looking for.

When in that case you can try those that I mentioned. In terms of coorporate AV, I doubt that open source AV has much enterprise support.

WinClam can be pushed down and installed silently on a remote PC, it can also be configured to automatically download virus definations and perform scheduled scans. These are pretty much the basic enterprise features it has.

If you are willing to spend, then McAfee has a pretty impressive enterprise security solution, and one that I would recommend you use.

http://www.mcafee.com/us/enterprise/products/anti_virus/file_servers_desktops/virusscan_enterprise_80i.html

Hope that helps.

Are you looking to run AV (free or not) or are you looking to actually secure your users from hurting you, your company and others? AV is a band-aid on a cancer...
If you want to secure your PC's, you need best practices.
http://www.xinn.org/win_bestpractices.html
http://richrumble.blogspot.com/2006/08/anti-admin-vs-anti-virus.html
http://nonadmin.editme.com/
I will personally put best practices up against every AV vendor, and I will win 98% of the time. And if i couple BP with firefox, or just about any other browser that is not IE or based on IE, I'll gain that last 2%. Even running IE as the lowest account possible, you can still install some malware like Vundo(virus) which is actually a BHO (browser helper object). I've moved more than 15,000 users down from admin's to the users group, with great success. In fact, my home, work and several clients do not run AV actively. Clam-AV on the email side, McAfee scan's PC's remotely for spyware/virii and comes up empty day after day... oh yeah and no IE. The only exception, and it's never bitten, but has the potential, is 0day virii. The latest one was MS08-067 http://news.google.com/news?&q=ms08-067, and the one before that was the WMF
http://en.wikipedia.org/wiki/Windows_Metafile_vulnerability but those as you can see are few and far between as compared to virri and spyware.
ClamAV is the main FOSS AV, it's very good, but I'd say overall, but is slower to get good signatures, and the heursitics behind. It's all we need however, McAfee makes sure of that and if we suspect ClamAV is missing something, the HD is pulled, and scanned as a secondary using McAfee and KasperSky.
Also, no one give me the admin rights are needed to run this and that, if you research and or work with a vendor, you can get around those issues. RunAs is an easy fix for most issues
http://xinn.org/RunasVBS.html failing that, it's registry and or file permissions 99.9% of the time.
-rich

Thank You,
That's exactly what i was looking for