Hey Hi,

you can do simply to open the SQL Server Configuration Manager.

Start -> Microsoft SQL Server 2005 -> Configuration Tools -> SQL Server Configuration Manager-->SQL Server Network configuration-->Named SQL server Instance-->then enabled TCP\IP and you can set 1433(sql server default port number) or 1434 or it depends what You want port number you can enabled...

You can go through below article

http://blogs.msdn.com/b/sqlblog/archive/2009/07/17/how-to-configure-sql-server-to-listen-on-different-ports-on-different-ip-addresses.aspx

all the best............

Thanks,..

kranthi