Basic + Push and pull
http://blog.slalom.com/2011/01/19/sql-server-replication-push-vs-pull-what-is-the-difference/
Multiple publisher replication + center subscriber
http://www.sql-server-performance.com/2005/multiple-publishers-replication/
MSDN: Snapshot replication
http://technet.microsoft.com/en-us/library/ms151832.aspx