Sounds like an announcement might be made shortly, with the league trying to get them back to work for this weekend's games. Backstory from the NYT:
The lockout began in June and centered largely around the issue of referees' pensions, which the league sought to eliminate and replace with 401(k)'s. The league also sought more control over replacing officials it deems are underperforming during the season. N.F.L. Commissioner Roger Goodell has come under fire as the officiating became a bigger issue in the third week of the season. He has said all along that his main goal is to reduce the bad calls that regular officials make by holding them more accountable. But the result has been a raft of poorly officiated games.
*Update: A source within the NFL Referees Association tells the LAT that a deal has not been reached, though negotiations continue. You never know in these situations, but it's possible that the referees are trying to leverage this week's uproar over the replacement refs. I'd imagine that they're pretty close.