Did you know you can shrink a transaction log even when log shipping?
- by simonsabin
David's posted a great post on shrinking the transaction 
log and log shipping. Log shipping and shrinking transaction logs
Unlike shrinking the data file shrinking the transaction log isn't a bad 
thing, IF you don't need the log to be that size.
I've seen many systems that shrink the log because it has grown only for it 
to grow the next day to the same size becuase of an overnight operation.
To reduce the growth of the transaction log you need to do one or more of the 
following,
1.Back it up more frequently2.Change to simple recovery model3.Use 
minimally logged operations4.Keep transactions short and small5.Break 
large transactions into smaller transactions6.If using replication ensure 
that your backup of the replication topology is frequent 
enough