My husband and I don't yet have any software, so 
we can't say anything about how well they work. 
But the one that we have been looking at is 
called L&H Simply Translating Deluxe. Follow the 
link I put in the URL line of the header and you 
can see the company's website. The price on the 
software is about $70. We liked this one because 
it seemed to have a bigger "dictionary" than some 
of the others - although all of them had the 
ability for users to add words if they wanted to. 
(What I can't figure out is how the user is 
supposed to add words to the dictionary if the 
reason they got the software in the first place 
was because they couldn't read the language in 
question. ^_^;)

It claims to be able to translate about 40 
languages, including all of the major romantics 
and germanics, as well as a healthy dose of the 
oriental/Asian languages. (Japanese is on the 
list.)

There are translation programs that cost up $300 
or more on the market, but - lacking any kind of 
real interactive experience with them - I can't 
tell you if they're worth the huge price tag. 
(We're not even sure this one is worth it's price 
tag, but at least $70 isn't breaking the bank if 
it doesn't toe the line.)

Insert here the required apologies to Yann for 
being off-topic. ^_^   If you want true humor, 
try to find the translated phrase Yann put up 
during one of the last discussions of translation 
software. It was almost as much fun as magnetic 
poetry. ^_^

Many Sharp Smiles,
--Drac