Jennie should be posting information about this swap soon. It will be handled like previous years SAB swaps.
If you are ordering tomorrow, go ahead and order the SAB items that you like. Jennie will work with you to ensure you get a spot in this swap with whatever stamps you have ordered.
Jennie and I work together so if you want to participate in both the Spring Mini swap and the SAB swap you can save on postage by sending the swaps to one address. More info to come in the next few days.