Update: 4th Feb Some Transcripts have been posted on Lostpedia.
LEFT
"You have to believe it's me, Nikki"
"Shush"
"Did anyone say something?"
"I said nothing"
"You better not say a f**king thing or talk about Desmond"
"It's Me"
RIGHT
I'm not going to listen to them"
"It's January 7th"
"I see somebody"
"Do you recognize him?"
Source: Lostpedia
Here is the audio enhanced for the whispers, followed by the same audio reversed.
Thanks to Mitch for the following.
I wanted to let you in on something you might not have noticed. I did some further sound editing on the files you posted that were enhanced and although most of it is indeterminable or foreign language, I did find two distinct messages. Thought maybe it was something you might want to pass along to your readers.
Keep in mind that there has been heavy noise reduction, so it may sound strange...but its the only way to get it semi clear.
I've attached two mp3's of the bits that I found that I think are phrases:
One says, "That Might Be Desmund", which is a bit up in the air.
And the next one, I think, is without a doubt a phrase being said. It states, "Joseph" and then (in another voice/from another person perhaps?) says, "So you heard somebody coming."
Source: The Company (Heroes) podcast