At the Fight Night chat event held this evening, Mortal Kombat series co-creator and team lead Ed Boon confirmed that character bios, which were not included in the original release of Mortal Kombat: Armageddon, would in fact be available soon on the official MK: Armageddon website. From the chat event:

[23:37:12] <@M4C> On a related note, shinken asks, "Are the MKA bios going to be released online?"
[23:38:03] <+Ed-Boon> Yes. We are going to be releasing the bio's on www.mkarmageddon.com
[23:38:57] <+John-Podlasek> Yeah, in the forums section....
[23:39:12] <+Ed-Boon> You will get the answers to all the questions you've had concerning the Armageddon storyline and perhaps even hints as to where it goes next

We'll be keeping an eye on this story as it develops; as soon as we know more, we'll be sure to report it here! Stay tuned, as we'll soon be posting the transcript from tonight's event and maybe a few pictures as well!