gOb, the links above might help you...
Ok, I guess I can't post links...makes sense actually, but go to kanjiclinic.com they have a Flash-based flashcard program that will really help your reading and basic understanding of Nihongo from beginning all the way to upper intermediate. Listen to what the other posters tell you, they are correct, but don't get overwhelmed. Your brain can only absorb as much as it is ready to at the time. Focus on your basic verbs first. They are important and you will understand why the more you learn.
Anyway, I studied Japanese in university and it helped, but not that much. I learned the majority of my functional Japanese while I was living there. You might have heard the advice to get a Japanese girlfriend/boyfriend (i don't know your gender or orientation, doesn't matter) if you want to learn Japanese, and while sex is an incredible motivator, guys run the risk of learning really "girly" Japanese and then using it because they don't know any better. I spent the better part of my first year in Japan hanging out with my Japanese co-workers, and basically being silent and just listening (I ate great food, drank a LOT, and tried to follow the conversation as best I could.) Try whatever phrases you hear and understand, ask them to let you order the food, etc, but the first part of the acquisition process consists of listening and imitating. (You can use this knowledge to help you teach better, too!)
I also found that on my off days, in the evenings, watching Japanese TV helped a LOT. Not the programs, you won't be able to follow those, but the ads. Being what they are, they have to be repetitive, catchy, and they really have to be understood by a mass audience so they generally don't use slang. Therefore, the vocabulary you acquire becomes very useful--"clean", "bright","helpful", "efficient", "cheap", "long lasting", you get the picture. It's not for everybody, but that helped me out.
The most useful thing you can do, though, is try to live a Japanese version of your life. Spent time with Japanese people. They are intensely interested in foreigners and will make time to be with you and are willing to help you understand their culture and language. Be patient. Japanese is not at all as difficult as people make it out to be, but it is VERY different, structurally as well as practically. I cannot tell you how many gits I have seen waltz into a year contract who don't learn Japanese and expect the world outside of them "Americanize/Canadianize/Austrailianize/Englandize" around them. It's a shame. I lived in Japan for three years, I learned (what I think) is passable Japanese, I'm certainly not fluent, but I made some great friends who I still have to this day and visit me in SF, and I have some really wonderful memories. Besides the weak salary they pay you, that's what you're there for, right? Soak it up and have fun. Eat some "weird food". Go on an awkward date. Participate in some matsuris. Learn i-Go from an old man. Enjoy it!