SQL Developer

Hi friends, I am trying to get the data from SQL Server 2005 to Oracle 11g using SQL Developer. As the first step I tried creating a connection for SQL Server.
1. New Database Connection ( connection wizard opens)
Connection Name: ss
selected SQL Server tab in this tab
I selected Use windows authentication
host name: localhost
post: 1433

and now i clicked test and retrieve database button both of these actions resulted --> Can not connect to Microsoft SQL server on localhost

also tried with host name as mourya (my computer name)

Please help me in this, Its very urgent.............

Thanks,
Pratap