Installing Linux on XP external drive

I bought an IBM Thinkpad T41 a few months ago. I love Linux, but Centrino support was not readily available at that time. I hear that the latest kernel now supports it. So, I want to install Linux on a removable 80GB IDE drive connected to the laptop via a USB connection. I can't touch the XP side since my wife only knows Windows. I'm fishing for the best way for me to boot to this external device when I want Linux. I have no floppy, but creating a boot CD is fine by me.

Can anyone assist???

Thanks
Ray