SPvP?
There's two PVP modes in Guild Wars 2; World vs. World (WvW) and Structured PVP (sPVP).
World vs. World is a large scale battle between three servers for control of four maps; three identical "Borderlands" for each server and one "Eternal Battleground" at the center. A large number of players (hundreds) work to capture keeps, towers and supply camps, escort supply carts, set up siege equipment and generally try to control as much of the four maps as possible. After two weeks, a winner is declared and the game matches three more servers up and the fight starts all over again.
Structured PVP is more like first person shooter deathmatches; you jump in and immediately start fighting other players in 5v5 matches. Right now we've only seen one gametype (Conquest, basically capture positions on a map) played on two maps. There are also tournaments which ArenaNet runs, and players can run their own tournaments as well.
Edit: Oh my god, stop stalking me Thanasis.