The one that I used the most for the interview prep was www.aviationinterviews.com. You have to register but it is completely free. The last time I looked there were several current interview gouges listed.
Congrats on the interview and I hope it goes very well for you.
The sim in STL is the Sabre.. either the 65 or the 80. The sim itself is old but flies very well. Kinda pitch sensitive at straight and level but in the steep turns, very stable. The profile is fairly simple only unknown is where you have to hold off the PDK VOR. Definately use your non flying pilot to help you out as much as you can. You are graded at both positions so you should hook up with your partner and work out a plan of action about what you expect from each other. The power settings that they give you for the different configurations worked for my partner but not for me, needed to fine tune it a little bit. Anyway, they have several thick binders that they can ask you questions from. Just be honest about not knowing the answer. The whole experience was great... Hope it works out for you.
ifyou want any specific questions they asked me PM me..