According to The Guardian, although nothing on the official site as yet.
I'm hoping we get some more detail on the signing over the coming days from both Lampard and Manuel Pellegrini regarding the reasons for the move. It is a low risk type of move and is generally being painted as a 'win-win' deal: City get an experienced hand for six months to feature in a few games and boost their homegrown quota, whilst Lampard can keep some sort of sharpness ahead of the next MLS season.
Do City really need to add Lampard to what is a crowded midfield already? At best, you have five spots up for grabs on a game by game basis (and this assumes Pellegrini doesn't play two up front). Now, looking at the squad these must come from the following: Fernandinho, Fernando, Yaya Toure, David Silva, Samir Nasri (the assumed preferred quintet?), Jesus Navas, Stevan Jovetic, James Milner and Jack Rodwell.
You look at the qualities Lampard has, and with his advancing years where will he best be suited? As one of the three behind the more creative players? This would seem to end any hopes for Rodwell to break through, or for Milner to get a shot centrally as opposed to out wide? All of this also assumes that Lampard is really going to oust any of the starters outside of the 'low risk' games?
Perhaps though, this is the aim of the signing. More of an eye on the season as a whole and ensuring a fairly overworked midfield is not too stretched heading into 2015.