I just bought this thing. Wonderful stuff. You can connect a 3.5" drive (with included power) or connect a 2.5" (laptop drive) without any power (uses USB drive for power).
http://www.pcmicrostore.com/PartDetail.aspx?q=p:10502715
PS: As you may know the 2.5" drive (laptop hard drives) are very compact, so can be used as a portable drive. I use a 40 gb drive. Veryyy convenient.
Re: IDE to USB Adapter
Intresting ....
I was lookin to buy the enclosure which does the same thing. I think that looks lil more slick and probably safer (has shock absorbant)
Re: IDE to USB Adapter
Ofcourse an enclosure is safer. But this cable is so portable. You don't have to carry around any power cables or anything, just whoop it out and attach people's hard-drives to a laptop via USB and do whatever is required.