I can't believe anyone is even questioning the phone call from Walt at the end, being anything but a calculated move to: Not only give Skyler some help with the charges, but also to let her seem like a victim in the eyes of Jr. It was very freaking obvious. Now you can discuss how plausible it is for Skyler to get off the hook with such an action from Walt, but there is no doubt about Walt's motivations with the phone call.
Edit: Also, as far as I know, this i supposed to be the final season of Breaking Bad? At the beginning of the season we saw a time skip where Walt comes back to his old house where you can see that a lot of time has passed. If this is the last season, and if that time skip is going to play any part at all (Other than telling us that Walt is going to get "exposed" in this season), I would predict this time skip to happen very soon.