Not quite sure what your question is... You say you know how to install it, so what's your question?
Just load up the installation disc of whatever distro you want, and install it.
If you want GRUB to have an entry for your Windows drive, leave it plugged in.
Otherwise, unplug it prior to installation, so that you can choose which HDD to boot off of from BIOS rather than allowing GRUB (or Windows bootloader) to manage it.