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!