Akama's Promise

The process of attunement to the Black Temple begins in Shadowmoon Valley with a very long quest chain that requires trips to the Arcatraz, Serpentshrine Cavern, Mount Hyjal and finally the doorstep of the Black Temple itself. Even if you're not planning on raiding just yet, the chain does offer some nice blue rewards half way through. It starts differently depending on whether you're Aldor (A) or Scryer (S):

Aldors pick up the line from Anchorite Ceyla in the Altar of Sha'tar:
1. (A) [70] Tablets of Baa'ri
2. (A) [70] Oronu the Elder
3. (A) [70] The Ashtongue Corruptors
4. (A) [70] The Warden's Cage

Scyers get it from Arcanist Thelis at the Sanctum of Stars:
1. (S) [70] Tablets of Baa'ri
2. (S) [70] Oronu the Elder
3. (S) [70] The Ashtongue Corruptors
4. (S) [70] The Warden's Cage

At this point the chains converge for both factions:
5. [70] Proof of Allegiance
6. [70] Akama
7. [70] Seer Udalo (Dungeon)

Here, you have to venture into the Arcatraz (which requires a Rogue with 350 lockpicking or somebody to open the door who's completed the Arcatraz Key chain, which requires trips to the Mechanar and the Botanica respectively) to the room just before the final boss. Sadly it's impossible to solo-stealth to. Finding Udalo leads to:

Talk to Akama:
8. [70] A Mysterious Portent
Kill waves of nonelites, 3 elites and a boss (5-man) on a terrace outside the Black Temple:
9. [70] The Ata'mal Terrace
Finally, deliver the medallion to A'dal in Shattrath City:
10. [70] Akama's Promise

The chain ends here, and you're granted a choice of rewards:
Akama's Sash (cloth DPS belt)
Bloodwarder's Rifle (gun)
Spellbreaker's Buckler (spelldamage shield)
Ashtongue Blade (phsyical DPS dagger)
Verdant Gloves (feral leather gloves)
Staff of the Ashtongue Deathsworn (healing staff)
However, if you now go into Serpentshrine Cavern and kill Karathress, you'll be able to talk to Seer Olum who'll continue the quest chain for you:

1. [70] The Secret Compromised
Go back to Warden's Cage in SMV and talk to Akama.
2. [70R] Ruse of the Ashtongue
Using the Ashtongue Cowl provided, kill Al'ar in Tempest Keep while disguised as a member of the Deathsworn.
3. [70R] An Artifact From the Past
You need to be attuned to Mount Hyjal for this. Simply kill Rage Winterchill and loot his phylactery (what is it with liches and their phylacteries?), then deliver it to Akama...
4. [70R] The Hostage Soul
...then return to Ad'al in Shattrath City...
5. [70R] Entry Into the Black Temple
...then go back to Shadowmoon and talk to Xi'ri on the road leading to the Black Temple. He'll ask you to help with
6. [70] A Distraction for Akama
...but once you tell Xi'ri you're ready (talk to him after accepting the quest), you can watch a scripted sequence that you do not actually have to help with in any way. After this is finished, talk to Xi'ri again for your Medallion of Karabor and the completion of Black Temple attunement. Congratulations, you can now waltz in to Illidan's latest bachelor pad!

But before you go, the chain continues from Xi'ri with:
7. [70R] Seek Out the Ashtongue
Time to start exploring the Black Temple! When you find the Deathsworn, they'll give you
2. [70R] Redemption of the Ashtongue
...which requires you to kill the Shade of Akama. Finally you're given
3. [70R] The Fall of the Betrayer
Yup, kill Illidan. No problem. Then you're done.

Once you complete this questline/quest you will be able to talk to an NPC who resides in a cage behind Fathom-Lord Karathress in SSC. After killing Fathom-Lord the NPC will be freed and you will be able to pickup a Quest which will be to return to Akama and report some findings.

http://www.wowhead.com/?quest=10944

When you get to Akama you will notice he is having a conversation with "Illidan's Presence". Illidan orders Akama to have one of his Ashtongue venture into TK to kill A'Lar. Akama passes this duty on to you in the following quest(line):

1. Ruse of the Ashtongue:
http://www.wowhead.com/?quest=10946
2. An Artifact From the Past
http://www.wowhead.com/?quest=10947
3. The Hostage Soul
http://www.wowhead.com/?quest=10948
4. Entry Into the Black Temple
http://www.wowhead.com/?quest=10949
5. A Distraction for Akama
http://www.wowhead.com/?quest=10985

It is at this point where you recieve the actual Medallion of Karabor which grants you access to the Black Temple, but the questline is not yet complete. The final quest awards The blessed Medallion of the Karabor which upon "use:"transports you to the entrance of the Black Temple but you need to kill Illidan to get it =)

6. Seek Out the Ashtongue
http://www.wowhead.com/?quest=10958
7. Redemption of the Ashtongue
http://www.wowhead.com/?quest=10957
8. The Fall of the Betrayer
http://www.wowhead.com/?quest=10959

Correction : You get 1000 reputation from the final quest with the Sha'tar