It sounds like you're looking for a restoration (healing) spec. The classes capable of healing are druid, monk, paladin, priest, and shaman. Racially there aren't a lot of significant differences, though specific races can only play certain classes. (Alliance races are listed below as well, though the original question was about Horde)
- Druid (Horde: tauren, troll; Alliance: night elf, worgen) - limited to leather armor; tree form (cooldown ability) increases healing throughput; good profession choices: skinning/leatherworking, herbalism/(inscription or alchemy), mining/jewelcrafting
- Monk (any except Horde: goblin; Alliance: worgen) - limited to leather armor; use brews and teas as the primary basis of skills; similar professions to druid (I've never played a monk healer, so can't really address the specifics...)
- Paladin (Horde: blood elf, tauren; Alliance: draenei, dwarf, human) - can train to use plate armor at level 40(?), limited to mail previously; some people think they are limited to single-target (tank) healing, but do have some raid utility too; professions: any of the combinations mentioned above, or mining/blacksmithing
- Priest (Horde: any except orc; Alliance: any) - limited to cloth armor; best professions: tailoring/enchanting or herbalism/alchemy
- Shaman (Horde: goblin, orc, pandaren, tauren, troll; Alliance: draenei, dwarf, pandaren) - can train to use mail armor at level 40, limited to leather previously; can also use shields; in addition to direct healing spells, also have totems that provide passive effects and healing; professions: similar to paladin
For all, you can learn first aid, cooking and fishing as secondary professions that will come in handy.
Note that resto is much easier to level as primary spec now that you get access to the LFD tool at level 15. And, they're in big enough demand that you shouldn't normally have queue times that are very long.
ETA: Cataclysm/Mists updates
I haven't played WoW in a while, but WoW builds are constantly changing. Because of this I think you'll find a constantly updating source helpful. I always found great information at Elitistjerks, mmo-champs and even in the wow-forums.
This a good guide for rogues in cataclysm. His update is from this month, so I believe this is a accurate guide.
Some good sample here, here and here
Ok some explanation now:
Why subtlety:
Subtlety rogues present a combination of DPS and utility
allowing them to do well in both PvP and PvE. In the DPS race an
Assassination or Combat build might pump out more overall damage, but
Subtlety is more fun and more flexible. And Assassination doesn't have
Shadowstep.
Subtlety rotations:
PvP:
There is no PvP "rotation." Try to lock up your opponents and burst
them down when you can. Glyphed Garrote silences casters Keep
Recuperate up at all times. The HAT talent helps with this, providing
extra combo points. You might even be able to start a fight with Recup
running. Try to keep Slice and Dice up, but not at the expense of
stuns. Rupture is good Vs stealthers. Learn to use Shadowdance and
glyph it (two more seconds.) Save your Shadowstep, if possible, until
the opponent escapes (eg: Blink,) then use it to catch up.
Check out the links. they are more complete, with Gems, runes, professions even races.
Sorry for the link only post, i used to see some http://jsfiddle.net/ posts on stackoverflow, and i like post the font with a link, by my mistake (was late) i forget post some content with it. Thank you for your -1
Best Answer
The Horde equivalent is Orgrimmar, the Orc capital. It contains portals to cataclysm areas, PvP vendors, as well as everything standard to one of the big cities (Auction House, banks, class and profession trainers, etc.)