how to dual boot ubuntu on secondary drive

I have to 320gb sata hard drive in my computer. I have Vista installed on my primary hard drive. How do I install Ubuntu on the secondary drive? Is there a way to install ubuntu from vista or is that even possible?
Ubunta on external drive

Two ingredients I found for getting Ubuntu on an external drive was to select the external drive in the partition menu and take the whole thing, then use the advanced tab when it's asking you where to put the boot file and make sure you put it on your external drive. How to dual-boot Vista with Linux (Vista installed first) -- the step-by-step guide with screenshots

However, I can't get Easy BCD to boot of the external drive, tho I can thru the bios. I've posted a thread on this Vista and XP issue - The NeoSmart Forums


Mostly Harmless
Staff member
Getting EasyBCD + external drives to play nice depends on how your BIOS is configured.

Some BIOSes will find external drives and list them, others will only detect that a mountable volume is attached... Depending on which is the case, when the bootloader (EasyBCD's part) is reached, the info on the available disks will differ from one machine to the other.