as a follow-up to my earlier post, Apple recently updated Boot Camp to support Windows 7.
it took me three days of arduous troubleshooting, but i finally managed to get Vista Business on Boot Camp on my October 2008-vintage MacBook Pro upgraded to Windows 7 Ultimate.
the process was not straightforward because for some inexplicable reason, the upgrade disc which i had bought from my university's computer store, refused to mount under Boot Camp in Vista (although it mounted perfectly under (a) Snow Leopard and (b) Vista on a regular PC). i finally resorted to connecting my MacBook Pro to an iMac using Firewire Target Disk Mode, and using the iMac's slot-loading optical drive to mount the installation disc.
hope this helps someone :-)