How do court hearings work?

My soon to be ex husband is out on a $100,000 bond for a felony 1 & a felony 2 of deliv of a controlled substance. he was arrested in feb 2010 & the last i knew he had a plea hearing sometime in march 2011. im wondering how long it should take for a sentence hearing and if its likey that he will go to prison & how long this process takes. (we are in texas) from what i read in the affadavit is that on the felony 1 he sold to an under cover office who was wearing a wire tap. any information is greatly appreciated, im clueless to criminal law.