I'm assuming your wife is Japanese? Then why are you even messing with teaching at a school? You hopefully have a spouse visa which allows you to work at any job. That's the way to go other than getting citizenship here.
I've been hired by 7ACT and other companies that match students to my level of experience of teaching. I get paid 3000 yen/hour at the station of my choice. Not good in the long run, but at least it's extra income in the short term. It also gives me more experience planning lessons for the students based on what they want to achieve.
Update on Interac: they gave me a load of bull saying that they're waiting to hear on the Kanagawa BOE concerning the contracts for the 2009-2010 school year before they could renew my contract. I had posted a comment on a forum such as this and it upset a lot of people. I got a nasty call from one of the trainers asking why I said such a thing since I misunderstood that my contract was not being renewed but everyone else's is. I told all of them in the office that if they had just come out and said that instead of leading me to believe otherwise, everything would be fine.
BTW, any company who gives you the English in their directions are run by a bunch of morons that have no clue of how to live in a foreign country. Interac is full of such morons, and I always had to demand they send everything in Japanese. The other companies I'm interviewing with are also sending English, and I have to request the map to be in Japanese.
My views on being an ALT: you've got your good schools, and you've got your bad. I ended up with 2 of each. The people at the good schools were more than helpful in helping me learn Japanese during breaks. The bad schools had issues of me learning their language. The down part is you have a lot of free time when you're not teaching or planning lessons. Most of the time you have to work 8:30am - 5:15pm even if you only have one or two classes.
Sorry for the long post, but if this saves someone the hassle, then it's worth it. Come to Japan only if you want to learn the language, experience a foreign country, and their culture. Once I become fluent in Japanese, I plan to get a regular job!