Replication Monitor
configuration Replication Alert
replication warning : Transsactional replication latency [threshold latency]
After this Select-->SQL Server Performance Condition Alert(under Type)--Then-->Select MSSQL$YUKON1:Replication Logreader Under Object
then Select-->Logreader:Delivery Latency(Under Counter)-->Then ur instance and alert if counter value.....
You have mulitude of options under Objects so choose as per need.
HTH!