There's 5 classes at present with more coming up. Down the road each class can also select a prestige class, but at present only one per each class is ingame. I imagine these will sound familiar to d&d players. Again don't hate me if my description isn't accurate.
Guardian Fighter: The sword and board fighter clad in heavy platemail armor ready for the rigors of combat. The guardian fighter fights with determined and forceful blows, focusing on a healthy mix of defense and offense and with an eye for tactic. The guardian fighter's class mechanics is block mode, raising the shield and blocking all attacks to his front and getting two new at-will powers whilst in block mode, and the block meter wich depleted every time the guardian fighter blocks an attack.
Great Weapon Fighter: Wielding a giant weapon, most often a greatsword and wearing scalemail armor, the great weapon fighter is the juggernaut of the battlefield. He fights with fast sweeping attacks capable of damaging multiple foes around him. The great weapon fighter's class mechanic is determination, a gauge wich fills up on taking damage and when activated gives increased attack speed and damage mitigation, making him capable of taking a beating and dishing it right back out. Additionaly he can use his stamina to sprint, allowing him to dodge or get right in the enemies' faces.
Devoted Cleric: A battlepriests who's weapon is their unwavering faith. No mere heal bot here, the devoted cleric is just as capable at smiting and controlling his opponents as he is supporting his party with his healing abilities. With his (might be mistaken) chainmail armor the devoted cleric is anything but frail and can certainly hold his own when required. It should be noted that he cannot heal himself as much as he can his party. The devoted cleric's class mechanic is channeled divinity, wich when activated grants him two new at-will powers and enhances his encounter powers with additional effects. The devoted cleric can use his stamina to dodge a short distance.
Trickster Rogue: The leather clad dagger wielding rogue class, the trickster rogue's arsenal is misdirection, trickery and assassination. Using their strong single target damage and superior evasive capabilities, he is able to outwit and quickly dispatch single targets. The trickster rogue is primarely a melee class but has some defensive capabilities as well. Just as the cleric he can use his stamina to dodge, and finally his class mechanic is stealth, wich allows him to become less a target and empowers his attacks.
Control Wiard: Wearing the robe and wizard hat, the control wizard, as the name suggests, controls the flow of battle with his arcane powers. He is a ranged attacker who shines at disabling his opponents by slowing, entangling, stunning and pushing them around. The control wizard is most attuned with the forces of ice, using them to his defense rather then wearing heavy armor. Additionally his apply a stacking debuff called chill, reducing their movement speed. His class specific mechanic is spell mastery, wich lets him slot an available encounter power of his chosing in his class ability, empowering it and allowing him effectively 4 encounter powers. The control wizard uses his stamina to teleport a short distance.
And supposably the next two classes soon to come
Ranger
Warlock (It's prestige class, the actual class will probably have a different name)
And the races, I think these are standard for d&d but for newbs like me a brief overview. This will probably be rife with mistakes.
Human: Self explanatory. Humans are a widespread balanced race.
Elf: Your standard tolkien inspired elf, a long lived pointy eared humanoid race. They are wise and patient as well as attuned to the forces of nature and the arcane.
Dwarf: Eh this is the DF forum, I'm sure no explenation is needed.
Short stout stubborn and bearded, based on tolkien's dwarves.
Halfling: Much inspired by tolkien's hobbits, the haflings are a tad more adventurous and mischievous. There are no braver adventurers then the haflings.
Half Orc: Half orc, half man, the half orc is contemplative by orc standards and violent and short tempered by human standards. Fitting in neither civilization, they are outcasts to both.
Half Elf: Or Half Man is you ask an elf, the product of intermingling between an elf and a human. Curious like a human but longer lived and wise like an elf, they are not recognized by either as kin but are generally accepted.
Tiefling: A humanoid who can trace his ancestry back to a denizen of the nine hells, the tiefling is much like a human but with features of a devil. Not persecuted as hellspawn but generally distrusted, tieflings may either sturgle with or embrace their dark ancestry.