Yes you can – but not directly.  To install boot camp 3.0 on Windows 7 x64 follow these instructions.

1. open command prompt in administrator mode
2. type “net user administrator /active:yes” hit enter
3. log out then log in as “administrator”
4. then open cd and navigate to “bootcamp/drivers/apple/”
5. run “bootcampx64”
6. once done reboot, logback in and turn off administrator account by entering “net user administrator /active:no”

viola! boot camp 3.0 on x64!

This successfully installed on my late 2008 model uni-shell MacBook (the non-pro single cast aluminium one).  Windows 7 managed to get most of the drivers by default, which was a refreshing change from XP and Vista (including the wireless drivers), but once BootCamp had installed the audio was fixed, and everything was great.  I installed the GeForce 9M drivers from nvidia.com and I was in action.