Double tax?? (Tokyo)

Hello
I recently moved to Japan and started working in Japan (full-time).
I have no income in the States for now but have some stocks and CDs.
It's my first time doing my tax outside US... Can I use turbotax?
or how can I file my tax-return ?
My "to-be" ex-husband keeps telling me that I have to pay $$ to IRS (CA and Federal) from whatever I earned in Japan...
but isnt it double tax..?

So all Americans working outside the US pay tax in the country you currently reside and to IRS in the States...??