Yes, you can use either 64-bit or 32-bit Ubuntu with WUbi. Look here:
Most versions of Linux use LILO or Grub, which expect to bootstrap themselves (directly from the MBR), then boot either Windows (on a Windows partition) or Linux (on a Linux partition).
My system is a 64 bit system. Is wubi a emulation if so then would have to run the 32 bit on my vista 32 bit. The question has to do with wubi not 32 bit versus 64 bit becuse I know the difrence.
No, Wubi is not an emulation. Yes, it can boot 64-bit Ubuntu Linux.