As a Broker the most important thing you should ask is What is in it for you... The real truth of the matter is as a Realtor you are your own boss and in control of your own business.
With that said you should be looking for a broker that will help guide, train, mentor and show you the ropes. Like Bill said many agents give up within the first 5 years because of lack of training.
When I was a "Newbie" man I thought I was thrown to the wolves.. I didn't have much support even though I was told I would.. But I was determined to succeed I looked towards my local board for classes and I took it upon myself to learn and grow.. Today I am a Broker and owner of my own firm.
You are in control of your own success and knowing what is in it for you is a key element. Make sure when you interview you leave knowing what plan the broker has for "newbie agents" to help get them on their feet and on the path to success.
As a new agent you will have tons of questions make sure you will have the support from you broker of choice to give you the answers.