What is the best language learning software? I want to learn some
Arabic and French before traveling overseas.

I'm assuming you mean any kind of course when you say "software," not
just computed based ones.

For French I recommend Pimsleur's audio courses. If you complete all
three of the courses you should be at level 1 on the ILR scale of
language proficiency or "able to survive and cope a foreign country."
The Pimsleur courses are very expensive but you may be able to get
them at the library. For further study, Rosetta Stone is also good,
and also very expensive.

Pimsleur only has one course for Arabic so if you want to go more in
depth than that you can use the Foreign Service Institutes's intensive
courses. If you use Pimsleur you'll probably want to pick up a book on
the Arabic writing system because I don't think Pimsleur goes into
that. Again, Rosetta Stone is good for more advanced study.

I recommend you stay away from Instant Immersion, Tell me more, Euro
Talk, or any other cheap programs. In fact, Rosetta Stone is probably
the only good software course.

I hope this has helped.

You can achieve great and fast results with Rosetta Stone dynamic
immersion method - this is a computer program that you purchase and
install on your computer - then you just install the disk for the
respective language every time you want to study and choose a lesson -
it contains about 200 lessons per language and always gives best
results.
They say this is the best way to learn arabic. 
Every lesson of the course develops 6 basic skills: 
- listening - they use native speakers to pronounse words and phrases;
- reading - develop you reading skills by linking the written language
to real-life objects, actions and ideas;
- speaking - dynamic speed recognition software is used to compare
your speech to native speaker's - you record and listen to your voice
till you are happy with your pronunciation;
- writing - use the dictation exercises - the computer checks your
spelling, syntax and punctuation;
- spelling and punctuation;
This is a great course - I bought it for my kids and I can not tell
you how happy I am with the results.
Rosetta Stone course is not cheap but gives best results. 
http://www.e-nter.com