I'm not aware of anything but it should be quite a simple process, this is for changing DS IP address but might give you a few things to think about:
http://www.symantec.com/docs/HOWTO80637
Do you have many scripted installs or Preboot configs? They're the trickier things to migrate from one box to another, otherwise I'd start with a new database, copy the settings across and back up and restore the Jobs as Bin files.
Keep the old DS going for a while and just use change agent config to move agents across, they should update the aclient automatically if you set that option. Or you could generate a new standard aclient.inp file (must contain all the setting you want) and use copy file task to copy to settings:aclient.inp. that will apply the new settings.
Once you have most aclients over, you can create a job in NS to move the rest over and retire the old DS. Make sure before you switch off the old DS that any remaining clients have an Altiris (NS) Agent installed.