[CentOS] Installing from USB flash drive

Wed May 26 14:59:13 UTC 2010
Bowie Bailey <Bowie_Bailey at BUC.com>

I successfully created an install media on a USB flash drive, but now I
have a minor problem installing from it.  Whenever I run the installer,
it insists on installing grub on /dev/sdb (the flash drive) rather than
/dev/sda (the hard drive where I'm installing everything).

Is there a way to convince the installer to put grub in the right
place?  Should I just tell it not to install grub and then do a
grub-install from a rescue prompt afterwards?