I went to Judy Tarver for the interview prep. It includes a mock interview. It was very helpful. www.pilotcounseling.com
As for the testing. I have been studying SAT test preps on the internet. There are alot of free services that have tests on Math and Vocab. You can also find free tests on science and aviation on the net.
For the sim prep, I am going to FSI Boeing in DFW. There is a 727 sim you can rent w/instructor for $325/hr.
Read the book Checklist for Success by Cage, and the Idiots guide to Job Interviewing.
I would say that any interview prep sevice that works with airlines could help (ie Air Inc.) Its just to get you comfortable. The more you have done the less prep you probably need. For the sim you generally fly the airbus but I don't think you need to go buy airbus time. I didn't do any sim prep other then computer stuff. You can get a picture of the cockpit but all the instruments are in the standard configuration. If you have not been flying much or do mostly vfr stuff it might help. The sim is just a basic instrument scan drill. turns, airspeed, vsi that sort of thing. If you have the cash and think it will make you more comfortable it might be worth it but not a must. As for the testing. You could study every day for the next year and you will still feel like an idiot after. SAT stuff might help a little but only general stuff. basic science, vocab, and these logics tests. Do look up sylagisms(sp) because if you go into those cold your screwed. But I don't think there is really much you can do for the tests. Hope it helped. By the way I interviewed October and it went well enogh for a job offer.