I would wait now with the transformation.
There are lot of talka about the incompabilities in tigers and leopards software raids atm.
Something about the tigers sr 3.6.4 not being recongized by leopards,3.6.5. The 3.6.6 is rumored to release in the next few weeks.
Dont know if then the problem will be solved? I mean, if your softwareraid version is higher than on the leopards installation disk,will that cause conflicts?
In theory it should work so long as the Apple is taking advantage of Matrix RAID (part of the ICH). If they are it will be independent of Disk Utility's software RAID. If they're using Disk Utility to make the RAID and then fudging things in EFI (I'd think that this would be doing things the hard way) then Silent Panda is correct. Assuming it's using Matrix RAID, once it's configured, all that is required is installing a driver at startup (through the usual method of a Floppy or Keydrive in Vista or slipstreaming it in should XP work). I'm not sure how Bootcamp would affect all of this though.