Just today they released the "Mass Effect Datapad" for iPhone/iPad.
This is a pretty cool app, as it's free :)
The nice stuff in there is, you get some messages from your crew through this app while you play through ME3, unfortianatly i allready finished Mass Effect, but i guess it would still work if i do another playthrough.
Another nice feature is that you can do small missions through this app and those missions will reward you with "readiness rating" for your ingame Galaxy at War map, which is pretty cool since just playing through singleplayer isn't enough to get a high percentage of readiness rating (my map capped at 50% after finishing all missions in ME3).
And this app will also give you access to the (ingame) Codex, always nice for the lore nerds (like me).
Another app that has been realeased a few day ago was the iPad game "Mass Effect Infiltrator".
Personally i am not a big fan of iPad (or iPhone) games and this one is no different, i just can't get used to the controls, sometimes it feels like the controls have a will of their own as you try to move to a certain point often the character will do the opposite.
I believe this game is made by the developers of Dead Space and has the same type of controls, so if you liked that game you might like this one as well.
I am however trying to wrestle my way through this game as it is a Mass Effect story and another bonus is that any intel you recover in this game can be added to you Mass Effect 3 readiness rating, so yet another bonus :)
I don't know why but i really do like all these mobile apps that tie into the game and give you other ways to improve that ingame readiness rating, other than doing multi-player in ME3 (which is also pretty cool).