This isn't something that sql server is traditionally good at. At least in comparison to some different datastores I've used. There are products such as CouchDB that have merge / merge synchronization as key principals.
what kind of data needs synchronizing?
How much delay is acceptable for cross country / continent replication?
If you are storing session state or other key/value type information and need to synch that, then you may want to consider looking into a distributed key value store instead.
Have a look at RIAK Enterprise.
I love riak's scaling model and how it performs under failure conditions.
Msg 3903.. The ROLLBACK TRANSACTION request has no corresponding BEGIN TRANSACTION.http://nosqlsolution.blogspot.co.uk/