A large part of this depends on wether you actually have a RAID controller. Your statement "because my hard drive is in a RAID array" leads me to believe that you may have SATA drives plugged into a motherboard controller.
If you have hardware RAID, by that I mean a PCI RAID controller, usually having space for at least 4 or more SATA drives, then you'll have no problems. As long as you have unpartitioned space on the drives, it will be smooth and easy to deal with. That is also true if you have SCSI disks behind a controller.
If you have RAID run by the motherboard, then you have software RAID, which gets trickier. The newest kernel, 2.6.11 is supposed to handle software raid, but I have yet to see a distro ship with 2.6.11 to date. The next generation of knoppix or whatever comes out next may have 2.6.11 as the default, so I would suggest using that. Kubuntu ships with 2.6.10, and that detected my mobo software RAID, but I didn't have any data on the drives I was trying to preserve.
I would strongly suggest trying out the live CD of whatever distro you want, checking to see if it sees your RAID. If you meant IDE drives, then you have software RAID on IDE, and I have never touched that, so I can't be of any help.