Transaction replication would be the best one to go for, just set up the right articles to replicate.
Edit, noticed 2012 in the post, is it SQL 2000 or SQL 2012?
If 2012
Change Data Capture
SSIS
Service Broker
MERGE
Could also be used depending how much work you want to do and how near real time the updates need to happen and also what edition (Std or Ent) of SQL you are using.