Get Dirk Zeller's book, Your First Year in Real Estate, either from the library or buy it. It talks about what type questions to ask, what to look for, etc.
Remember, you are actually interviewing them more than they are interviewing you. They are not "employers" since you will most likely be an independant contractor.
How much training they "make" you go through varies from office to office. However, you need to find out the type and quantity of training each office provides. And, how much it costs.
There is much more, get Zeller's book.