There are eleven 'standard' classes for 3 rd Edition. They are the Barbarian, Bard, Cleric, Druid, Fighter, Monk, Paladin, Ranger, Rogue, Sorcerer and Wizard. Each class gets roughly 2-3 pages devoted to it. The descriptions include things we are familiar with like level and spell progression charts, as well as new items like class skills. Here are some tidbits from the classes chapter that you might find interesting.
Clerics can now turn undead only a limited number of times per day.
The various classes are also not automatically prohibited from using certain types of weapons or armor. Wizards can even wear armor if they wish, although each armor type imparts a certain chance for spell failure if the spell contains a somatic component. The skills chapter lists and describes the various skills that each class may learn. Each class has a selection of its own class skills that may be learned normally, a selection of cross-class skills that may be learned at an increased skill point cost and a selection of prohibited skills that may not be learned because they are exclusive to another class. The mechanic for skill resolution is very simple.