BitDefender is a program to check for Windows viruses and malware. It can be run in the background or on demand when required. Once installed it can be found under Applications - Systems Tools. It can be used as an alternative to clamav/clamtk.
An updated method of installation for BitDefender using Ubuntu 11.04 is described here:
Add the repository by going to System - Administration - Software Sources, click on the 'Other Software' (previously 'Third Party Software') tab. Now click on 'Add' and enter
deb http://download.bitdefender.com/repos/deb/ bitdefender non-free
Click on 'Close' and press 'Reload' when prompted. Ignore the 'public key is not available' message (as we'll add it next) and press 'Close'. Now in Applications - Accessories - Terminal add the repository key:
wget http://download.bitdefender.com/repos/deb/bd.key.asc sudo apt-key add bd.key.asc
Now update the apt cache with
sudo apt-get update
Install the graphical interface and command line program (2 files) with
sudo apt-get install bitdefender-scanner-gui
Once complete you now need to log out and log back in again. a menu shortcut will be generated (Applications - System Tools - BitDefender Scanner).
Before running the scanner it's probably best to install the latest virus/malware signatures by clicking on the 'Update' button.
BitDefender comes with a standard 30 day free license, when first installed. It is free for private and personal use - the license can be extended to one year by requesting a new license key from http://www.bitdefender.com/site/Products/ScannerLicense/ For all business use a paid for license is required.