I don't want to burst anybodys bubble here, but you may never get called from the pool.
You are scored on your interview and sim ride and rated in a league of sorts. Top of the league gets next groundschool. If you only scored average, then someone could interview after you and score better and get a date before you!. I know a number of people who have been swimming since august last year!
I am still technically in a pool for USAJet, and it is run as Thrustport said-they offer class slots to the "best" poolies first.
"Honey, do you know who the best pilot is? You're lookin' at him!"
(No not me! It's a quote from the movie "The Right Stuff"-actor, Dennis Quaid)
The USAJet training guy did say, however, the "best" pilots (this is pre 911) are typically only in a pool for about a month, because they get picked up by someone else if you don't call them. I have heard of several pilots with multiple class dates open, and when they report to one class, it opens up spots at several other airline's classes. If you tell them you are available on short notice, you may be able to get in sooner. Just be ready for an evening call telling you to be in class the next morning!
Good luck to all of you, whether looking for a job, waiting for one to reappear, or flying on line!