If you want to zoom in closer to an object using a camera phone and retain semi decent image quality, get up and walk closer to it. (and no, I'm not trying to be a smartass... )
Digital zoom just works on extrapolation of each pixel so you're going to lose image quality if you use digital zoom. Like sixone says, if you're concerned with image quality, use an actual camera with an actual zoom lens.
If you just want to take a picture of your dinner to post on Facebook, then the phone will probably suffice.