Nope, 64bit Windows are out of the, erm, window
Oracle, like Apple, don't want anything to do with MicroSoft by the looks.
NOTE: The rest of their software will run fine, you just won't be able to integrity check or fix (this includes rebuilding indexes!!!).
You'd be a fool to run a large DB (and I'm talking 40Gb plus, our busiest DB's can have more than 600,000,000 transactions per table per day!!!) without integrity checking.
Rumour has it, archiving will be the next to drop Windows support.