I downloaded this little beauty some years ago. My coachee Damien was so impressed when we used it in tuition a few weeks ago that he asked how he could get one and was amazed to learn it is free. Read about it. The only odd thing is the condition of use: Use of the free version is subject to license terms: it may not be used by people owning an SUV and taking more than four flights a year.
I have just downloaded the new version, which includes three additional free online features integrating it with Wikipedia and an online dictionary search. The basic program works off-line.