Your question is too vague to give a good answer.

There are three types or replication that could work for
this.

Snapshot, where you send all the tables and their data to
the subscribers. This will replicate all data even in
tables with no primary keys. The problem is that you have
to send all of the data over the wire everytime, and is
not a good solution when you have a low bandwitdth link
between your publisher and subscriber. If a large part of
your data changes between sync's you should consider it.

Transactional, where the transactions flow across the
wire. The downside of this is that only tables with PK's
on them will be replicateable. The upside is that its way
fast, and works quiet well on low bandwidth solutions.

There is also merge which adds into own key to all of your
table. Merge replication is more difficult to
troubleshoot, but works well in low bandwidth solutions.

Check out http://www.mssqlserver.com/replication for a
replication tutorial.
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