The Washington Post
says (reg. req'd) that CBS's lead expert did not authenticate the memos. Their other expert already weighed in and said they are fakes.
CBS News is stonewalling and now righties are speculating about why they would stonewall. This is the reasoning, they say, that this story should continue to have legs: if the memos are fake, CBS has no journalistic issue that prevents it from naming its source. In fact, at that point it actually may have a responsibility to talk about its source. If the source turns out to be interesting - say, the Kerry Campaign or the DNC or such - it has massive political implications, of course.
So they may be trying to figure out whether they can ride out the storm, or if they can't, whose heads have to take the damage or what approach leads to the least residual damage.