Before you buy this, you should know that it is only the first half of the comprehensive French I, and if you're traveling independently (as I was), you'll need the whole thing. After finishing off the 16 lessons of this, I found that my local library had the comprehensive set, and was able to use that to prepare for my trip.
That said, the Pimsleur method is stunning. The first few lessons can seem a bit frustrating--all you learn is different ways to say "Do you speak English?" and "Do you speak French." What you don't realize is that the program is actually giving you a sophisticated introduction to French sentence structure just using a few words, and you fly ahead from there.
Where this differs from tapes that just give you phrases is that it actually gives you the ability to form your own sentences, adapting to different situations. The program never teaches you specifically how to handle, say, getting a room in a hotel, but when I was backpacking through small villages in France, I was able to handle this without a hitch.
You will need a phrasebook or a dictionary on your trip to fill in the vocabulary gaps, and if you plan on counting past fifty or saying anything in the past tense, you will need to obtain the comprehensive program. But if you're going to France in a tour group and just want to be able to understand a bit of what's going on around you, this is perfect.
The effectiveness of this program cannot be overstated. My library has levels II and III. I'm planning on going through those and heading off to backpack in Quebec this summer.