Found all of the anniversary terminals including the secret 11th one. If anyone noticed the codes of each code at the end of the terminal, I just deciphered all of them using halopedia. The codes mean:
"The Pillar of Autumn": 343
"Halo": HALO4
"Truth and Reconciliation": SPARK
"The Silent Cartographer": FLOOD
"Assault on the Control Room":EARTH
"343 Guilty Spark": DEMON
"The Library": RINGS
"Two Betrayals": ARRAY
"Keyes": HUMAN
"The Maw": HAVEN
Here's the link for the translations of the symbols:
http://halo.wikia.com/wiki/Terminals_-_Halo:_Combat_Evolved_A nniversary
EDIT: Apparently, there was originally another secret 12th terminal. It ha now been removed by 343, but if you were able to find it, you would need to type in a secret code. Once unlocked, there would be something under the "Alpha Halo Archive" where you would find the other 11 terminals. This new section and all of its contents only say "???". The terminal shows a color testing screen and tone and has subtitles.
12th terminal "???": WAKEUPJOHN
"For decades, we've fought an alien enemy we don't understand. Unprovoked, they brought our civilization to its knees, and forced us into hiding."
Link for 12th terminal:
http://www.youtube.com/watch?v=EGTir7T8W54
[Edited on 12.04.2011 4:18 PM PST]