What is Service Broker in SQL Server

Service Broker in Microsoft SQL Server 2005 is a new technology that provides messaging and queuing functions between instances. The basic functions of sending and receiving messages forms a part of a “conversation.” Each conversation is considered to be a complete channel of communication. Each Service Broker conversation is considered to be a dialog where two participants are involved.


Service broker find applications when single or multiple SQL server instances are used. This functionality helps in sending messages to remote databases on different servers and processing of the messages within a single database. In order to send messages between the instances, the Service Broker uses TCP/IP.


More Detail and example:
http://blog.sqlauthority.com/2009/09/21/sql-server-intorduction-to-service-broker-and-sample-script/