I am using Ubuntu 11.10. I had installed
clamtk, but it failed to update itself to the latest version so I uninstalled it. Now I want to install the latest version of
From the official site's downloads page for Linux, the latest version of ClamAV which has been "at least lightly tested" for your Ubuntu release is available in the Ubuntu backports repository. See here on how to enable this repository: How do I enable the "backports" repository?
Official instructions for obtaining and compiling source code for yourself are provided here.
Announcements of new ClamTk versions are posted on the front page of the official ClamTk site. There you can find a .deb download link for Ubuntu/Debian and install from there. You can also go straight to the Sourceforge download page.
Keep in mind you will have to use ClamTk to check for new versions or check the website yourself regularly for when new versions become available.