unfortunately, Google is yet to release a Linux version of Google talk. however, you can access your Google talk account using any of the jabber compatible clients available for Linux. these include pidgin (which is installed by default on most distros), empathy and others. pidgin however does not have voice and video support. empathy on the other hand, has been proven to support voice on the Google talk protocol so i guess that would be the logical step to take.
depending on your distro, there are several ways you could install empathy.
hope this was useful. cheers
