The Manchester Evening News claim City are preparing a £15m bid. I honestly think there is truth in this rumour. It seems to have run for a while now, and there isn't a denial from either City or Everton.
Moyes has come out and said he doesn't have to sell, which makes me think he's doing either: (1) encouraging City to raise their game to offering something starting with a 2; or (2) actually telling the truth, and he really does mean no-one is for sale.
The problem is, if Joleon isn't for sale, I don't know why Moyes doesn't just come out and say: Even if you offer us £20m+, the lad's going nowhere. He's contracted, and I will under no circumstances let him leave the club.
Until Moyes comes out with a statement like that, the rumours will continue until either Joleon is sold, or City move on to another target due to being unwilling to match Everton's very high valuation.