You can't really move the LS. Just deactivate the old W2K LS, install
and activate the new 2003 LS and re-install your licenses using the
telephone method. A Windows 2003 LS can handle both W2K and 2003 TS
CALs and doesn't need to run on a DC anymore.
Note: if you also upgrade your TS from W2K to Windows 2003, you will
need new 2003 TS CALs.