ClamWin Alternatives

ClamWin

[Please note that ClamWin Free Antivirus does not include an on-access real-time scanner. You need to manually scan a file in order to detect a virus or spyware.]

ClamWin Free Antivirus comes with an easy installer and open source code.
High detection rates for viruses and spyware; 32.4 MB download.

It features:

High detection rates for viruses and spyware;
Scanning Scheduler;
Automatic downloads of regularly updated Virus Database.
Standalone virus scanner and right-click menu integration to Microsoft Windows Explorer;
Addin to Microsoft Outlook to remove virus-infected attachments automatically.
Available in 7 languages.

Available also in a portable version:
http://portableapps.com/apps/utilities/clamwin_portable