>>3 SIRI is the iphone's attempt at doing this. I don't have an iphone, so I can't vouch for or against it, but I hear that it screws up a lot. Also, Jarvis on Iron Man has a lot more functions and abilities. (ie: jarvis can recognize objects and launch Iron Man suits and whatnot.) Siri does have voice recognition and the ability to use some of the apps on the iphone though.
>>1 I would say that Jarvis will be built in the future, but is years, maybe decades off due to the difficulty of object recognition software, and the bugs in the intelligence part of the software (planning, getting around obstacles, ect.)