Hello Brian, The D7000 uses a different battery (En-El-15) and as far as I know you have the choice of an additional En-El-15 or 6 AA's. I have seen no mention of the D90 batteries working in the D7000.
Marc There are always two people in every picture: the photographer and the viewer.-Ansel Adams
#2. "RE: batteries" In response to Reply # 0 Tue 12-Apr-11 02:59 AM by grosda
I'll answer your questions in reverse: Yes, the D7000 uses a different battery than the D90. The good news: the new model has a great battery life. I used to carry four batteries with me for a days sport shooting with my D90. I can shoot several hundred shots over several hours and not use an entire battery with my D7000.
The D90 batteries do not fit the D7000 grip (per the manual).
It is a bit of a disappointment to have to incur the additional expense, but the new battery system is good. I still carry and use both cameras.