Can i implement a wireless connection between an embedded system and a mobile phone?
(1) Yes. 

(2) It's largely a matter of having the "correct" hardware either in the phone or available via some intermediate interface. 

In the case of typical "smart phones" with 802.11* "WiFi" capability it's entirely a matter of "just doing it" at the phone end. 

Examples only - If using Android O/S phones 

Here is a WiFi manager App with 6 or so related links in the left hand menu

WiFi analuzer

Someone's 4 of the best WiFi apps list


Here are 4 of the best Android apps for Wifi.
These apps allow you to 


find public wi-fi networks, 
turn your phone into a wifi hotspot 
and a bit more.





Then there's "approaching it from the other end" - rather than interfacing  Android to an embedded system, add Android capability to an embedde OS and then use whatever is available "within" Android natively (ie just about anything).

Android porting guide for embedded systems. Essentially Android on ARM. They say - 


Android is a Dalvik Virtual Machine based software platform that runs on a Linux based kernel. Therefore,
to port an Android platform, one needs to port the underlying Linux OS and then the Android platform
SDK as well. This document explains how to port the Android platform to custom ARM based boards.
ARM is one of the most popular platforms for embedded devices




and

Android for embedded systems


At the end of this workshop, participants would be able to design custom Android Applications that can be used to access and control remote embedded systems.