[Sangetsu]

Your American credit cards will work fine in Japan, however, you are probably going to find that less than 50% of shops accept credit cards. Credit cards will not work at McDonalds and other fast-food restaurants, and the only convenience stores which accept a credit card is Lawson. Japan is very much a cash-oriented society; there are no extra fees or interest for using cash, robberies are very rare, and ATM machines have no limit for withdrawals.

High-speed internet is widely available in Japan, and there are many service providers. The simplest provider to deal with is Yahoo. You can have someone at your school help you get it set up. I'm sure they'll have someone there who is going to guide you down the steps of getting your ARC (gaijin card), opening your bank account, and getting your apartment utilities set up.

You might find paying your American credit cards from Japan to be difficult. Overseas bank transfers are expensive. In Japan is common practice to mail cash, and the post office has envelopes for that purpose. However, you aren't supposed to mail cash overseas. You can still mail it, you just put it in a regular envelope. You'll need someone in America to deposit it for you. A good option to think about is getting a Visa or Mastercard debit card (or credit card, if you can get one) from a Japanese bank. If you have either, you can easily transfer money via paypal. Just set up 2 paypal accounts, one linked to your American bank account, and the other to your Japanese credit/debit card. You'll be dinged a few percent on each transaction, but the cost is still far lower than using a wire transfer or Moneygram (which is only available in one bank in all of Tokyo, Western Union left Japan nearly a year ago).

As for your hair, as long as it isn't bizarrely styled, or the color isn't glow-in-the-dark blond, it shouldn't be a big deal, particularly at a private school. Students and J-faculty are usually prohibited from dying their hair (or even wearing makeup), so if you want to fit in (as much as that is possible), get your hair back to it's natural color.

I'm coming up on my third year teaching here in Japan, and I love it. I hope you have fun too.