Upgrading drives in a RAID 5 array

I need some advice regarding upgrading the drives sizes on my RAID 5 array. I currently have 3- 9 gig drives setup on an Adaptec controller as a RAID 5 array. I want to replace them with 3- 36 gig drives for more space. I had thought about using xcopy to dump all data ( about 12 gig currently) to another machine, rebuilding the array and then dumping it back. Will this work? Any other suggestions?