How do I use Web.Config transform on my connection strings?

In my current project, I have some connection strings that are valid for local development machines:

<configuration>
  <connectionStrings>
    <add name="ApplicationServices"
         connectionString="Data Source=localhost;Initial Catalog=MyDB;Integrated Security=SSPI"
  </connectionStrings>
....
</configuration>

How would I use the Web.Config transforms to convert from this expression to one valid for our production server? The production server one would look something like:

<configuration>
  <connectionStrings>
    <add name="ApplicationServices"
         connectionString="Data Source=IPAddress,Port;Initial Catalog=SomeOtherDB;User ID=TopSecretUsername;Password=SecurePassword"
  </connectionStrings>
....
</configuration>

The syntax isn't obvious to me, and I'm completely failing at grokking the page on it.