Maybe.
If you use one you put together yourself and didn't load any PASSWORD or ONE TOUCH BACKUP (carp) software it will work.
If you don't own a Phillips screwdriver you can run into that issue with those drives from the usual names. A call to the drive's maker should reveal how to fix that.
Bob
Quick history of why I want to know. I currently have a desktop with all my family stuff on it; music, photos, videos, and other 'family stuff' or should i say junk. Anyway, I don't want to transfer it all to my new laptop but at the same time I wont throw them away. I am getting rid of the desktop and going to a laptop only. I am using XP now and am getting vista on the laptop. I am about to get an external drive and just dump all those things onto the drive. Can I just plug and play the external hdd into my laptop running vista even though all the info was loaded into the driver using xp?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic