SQL Server 2008: Diff table data on different servers with exact schema
Is creating a linked server on one of those an option?  If so you could probably do this using something similar to the following query (untested):

INSERT INTO Server1.db1.dbo.Table1
SELECT * FROM dbo.Table2
EXCEPT
SELECT * FROM Server1.db1.dbo.Table1


If not, then maybe take a look at SQL Server replication