Basic Information from Blizzard regarding Orcs:
The savage, green-skinned Orcs are one of the most prolific races of Azeroth. They are commonly believed to be brutal and mindless, possessing no humanity or empathy for other races. Born on the hellish world of Draenor, the Orcs were brought into the kingdom of Stormwind through the dimensional gateway known as the Dark Portal and forced to wage war on the Humans. Although few are aware of their history, the Orcs once cultivated a noble, Shamanistic society on the world of Draenor. Tragically, the proud Orc clans were corrupted by the Burning Legion and used as pawns in the Legion's invasion of Azeroth. The Orcs managed to rebel, however, and they were ultimately able to help turn the tide against their demon masters. Led by the young Warchief, Thrall, the Orcs have reclaimed their strength and honor. Now, the Orcs stand ready to fight not for the sake of conquest, but for their right to survive in their adopted world.
Start Location: Durotar
Home City: Orgrimmar
Available Classes: Hunter, Warlock, Warrior, Shaman, Rogue
The TenTonHammer take on Orcs
Aside from the coolness of walking around as the “not so jolly” green giant, the orcs are a race in majority amongst the side of the horde. It is the orcs that form the main opponent of the Alliance and will continually make raids against Alliance Territory in an effort to weaken their enemies.
Orcs start in the city of Durotar, with their main city of Orgrimmar being only a few minutes away. The lands of Durotar will provide ample adventuring ground for any newly started character or group of horde characters.
Links to information on other WoW sites
Blizzard WoW site - The official Blizzard WoW Orc information page.