Wordfast Professional is a more recent incarnation of Wordfast, one of the most popular CAT tools.

Wordfast Professional differs radically from previous design of Wordfast (which will remain available under the name "Wordfast Classic": rather than being written in MS Word's macro language and using MS Word as its primary user interface, Wordfast Professional follows the Java route and is therefore a standalone application, independent of MS Word/Office. Being a Java application, it also runs on Linux.

Link to the Wordfast website

Link to the Wordfast Professional user forum (all platforms)