If they are played right by someone who is good at warlock pvp, then yes, they are good.
Just like any other class, if a bad player is playing an undergeared character badly, then they will be bad. If a good player is playing a correctly geared, gemmed and enchanted character in a good way, then they will be good.
Laughing Skull is a pretty good Alliance PvP server as is Wildhammer on the US realms
There are many places where one can find World of Warcraft PVP strategy tips. One of the best places where one can find World of Warcraft PVP tips at places like GameFAQs.
All PVP type servers in WoW have lots of PVP going on, including Daggerspine.
Sylvanas
One can find a guide on World of Warcraft warlock PvP builds on noxxic dot com. Additional information can be found on wowhead dot com and wowwiki dot com.
Adventure quest world is really cool and it has PVP sword battles
When you play WoW, you have to choose a server to play on. This is a list of the different types of servers:NormalPvPRPRP-PVP
There are Battlegrounds (more every expansion), and on PvP servers there is world PvP - more so now that Blizzard has implemented Cross-Realm Zones. PvP servers often have PvP oriented guilds that can help show you the places members of the enemy faction congregate. The recent Pandaria expansion is a good place to start if you are level 85+, the leveling zones in Pandaria a veritable hotbed of PvP.
Yes there is a Realmlist for World of Warcraft the most common ones are Pvp,Normal,RP Some of the realms: Stormreaver,Bladefist,Area 51,Ghostlands,Warsong,Anub'arak
Go player versus envirment you can still do some pvp but its the best way to start
Akama but Bg's and arena go through all realms on a sever.
For a warrior, well obviously you want protection for tank, fury for raiding and arms for pvp.