In CRM 4.0, in order to assign an item to a queue with a workflow, a user would add a step and use the "assign" feature and select the appropriate queue. In CRM 2011, it doesn't work the same way--you no longer use "Assign" to add items to queues.
In order to route an item to a queue, a user must create a new step using Create Record feature in their workflow. After the user creates the new step, he/she will select "Create: Queue Item.”
Once the user has selected “Create: Queue Item” all the user needs to do is identify the appropriate values on the Set Properties screen. In this example, we set the Queue to “Implementation” and the queue item to the primary attribute of the enitity that we want the workflow to route to the queue, in this example, a custom entity we created called “Service Orders."
If the user wants to change this item from one queue to another, later in his workflow, all the he has to do is create another step later in the process to create a new Queue Item.
by: Sean Shilling,