This is a Windows service that is installed when you run the SQL Server install. But it is not turned on by default.
The SQL Server Browser service is responsible for enumerating SQL Servers and allowing applications to discover and conect to named instances without specifying a port number or pipe name.
You should configure it to start automatically if you need:
* If running, it allows you to connect to a instance of SQL Server running on a non-default port number
* Allows you to connect to a named instance of SQL Server 2008 without having to specify a port or pipe
Typically, the SQL Server Browser service can be configured to run using the Local Service account, which is an account with minimum permissions.