Always Two Queues?

I'm just getting around to understanding notification services in sql 2005 and I have been working through some examples.  I'm curious as to why there are always two queues and two corresponding services being set up even when both queues/services exist in the same database.  Here is my ultimate goal.  I want to have triggers put messages on the queue for various stored procedures to handle asynchronously - i.e. table xyz is updated, and I need a stored proc to take the updated values and possibly generate or update rows in another table.  When I tried to set up one queue and one service, nothing ever seems to get put on the queue:

Create Message Type TestMessageType Validation = Well_Formed_XML;

Create Contract TestContract (TestMessageType Sent By Any);

Create Queue TestQueue;

Create Service TestService ON Queue TestQueue(TestContract);

Begin Tran;

Declare @DialogHandle UNIQUEIDENTIFIER;

Begin Dialog Conversation @DialogHandle

From Service TestService

To Service 'TestService'

On Contract TestContract

Send On Conversation @DialogHandle

Message Type TestMessageType (N'<message>Hello World</message>');

End Conversation @DialogHandle;

Commit Tran;

Select * From dbo.TestQueue;

(nothing is ever returned)