SCCM 2012 – Migrate from SMS 2003 to SCCM 2012

There is no directly migration from SMS 2003 to CM 2012. Only the migration from CM 2007 SP2 to CM 2012 is possible and side by site. Therfore you have 2 way : SMS 2003 --> CM 2007 SP2 ---> CM 2012 or strat with CM 2012 from zero and forget SMS 2003 (there is no tool in this case to migrate package).