Here is a compilation of some useful sites and addons for those learning about PvP. While addons are not necessary to be the best (the tournaments for the very elite even prohibit addons!), they can be great training wheels for teaching yourself to pinpoint targets, deal with CC and learn awareness of objectives. As with anything, practice will help you improve, and reading up on the topic will also help you learn the more intricate details of PvP!
The following websites offer useful information about PvP combat, gearing, strategies and so on.
http://www.arenajunkies.com/ – Great overall PvP resource. While this site does have a paid member option, you can still get a ton of info as a free user. Macro libraries, spec and gearing discussions, active forums with lots of combat strategies and discussion.
http://elitistjerks.com/forums.php – This site is more focused on PvE, but it is still a very high quality resource, especially for information about min/maxxing, spec/gemming, rotations, and theorycrafting.
http://wow.joystiq.com/category/blood-sport/ – WoWInsider’s PvP sections offer great information, especially for those new to PvP. This site has a more casual focus, although the older articles (http://wow.joystiq.com/bloggers/c-christian-moore/) have some good breakdowns of more advanced tactics.
The following add-ons are super helpful for PvP!
http://www.curse.com/addons/wow/healers-have-to-die – “Healers have to die!” is an excellent BG addon, especially for DPS. The addon will identify who healers are and clearly mark them in your UI for easy burning/CC.
http://www.curse.com/addons/wow/battlegroundtargets – “Battleground Targets” helps you pick out enemies, find weaker targets, pinpoint healers and see how many teammates are focusing a target. Very vital for DPS to have!
http://www.curse.com/addons/wow/losecontrol – “Lose Control” is a great, lightweight addon for CC. Blizzard copied this addon in 5.1 with the CC splash text, but lose control is much smaller and has a clear graphical display over your character cycling down how long a CC on you will last. Far less obtrusive than the default UI and it’s easy to see, at a glance, how long you’ll be stuck.
http://www.curse.com/addons/wow/gladius – “Gladius” is the number one arena addon. It replaces the default arena UI and includes a lot of customizable display options to show things like trinket use, CC duration and alerts for drinking and rezzes being cast. You can also setup the frames to have actions cast with various mouse button clicks (eg bind right click to a spell).
http://www.deadlybossmods.com/ – “Deadly Boss Mods” is something people might think of right off the bat for PvE and raiding, but there is also a great module inbuilt for battleground PvP! With this addon, you can see who is holding each flag for maps like Warsong Gulch and Twin Peaks, and you will see countdown timers for how long a node will take to cap or how long until a match is won.
If you are fanatic about PvP and want more ways to group with people, check out these options:
http://www.openraid.us – This site uses the battletag system to let people group up cross-realm. There is a realtime chat (like IRC) for pugging groups, as well as scheduled events you can sign up for, as well as forums. There are also public mumble servers available for free use.
http://battlemasters.org/ – Similar to openraid, Battlemasters is run by a highly-ranked PvPer, Eldacar, and provides players with a chat tool/IRC to quickly form groups across realms using battletags. There are also blog posts discussing PvP, forums and a free vent/mumble servers available for use.
http://solidice.com/oqueue/ – oQueue is an innovative merging of community and addon. The addon links you up to a large network of other users and allows you to queue, in game, for cross-realm BG groups and RBG matchups. Be sure to watch the tutorials on the website or join the facebook group if you have any trouble figuring out how it works.
Please feel free to reply here with your own suggestions for addons and websites, and I will add them in to the original post!!!