I don't know anything about Macs...but recovery software would probably do the job, if the partitions haven't been written over.
Some options are listed at http://www.tomshardware.com/forum/232360-4...leted-partition
I do have familiarity with GetDataBack for NTFS, but I've not used any of the others I see listed.
Many of us probably has a data recovery program we've had success with, but there are so many programs available that it's hard to familiarize with many of them (once you've found one which works satisfactorily).
Some are free, some are paid. I have a bias that says that paying for one results in more satisfaction, but that's not necessarily true.
Since you say that these are external drives, you need to ensure that whatever program you use properly sees external drives connected via USB, just as XP's Disk Manager does.
Edited by hamluis, 04 February 2010 - 12:45 PM.