Download fring in your phone and use it as SIP phone to setup freecall.

After seeing your qn i tried it, i was already having fring in my phone, i setup the sip account with freecall settings and it works. the user name/password should be your freecall user name/password (no need of any "@") and the proxy server : sip.voiparound.com

You cant see the balance in that, but still its a cool setting.. thanks for initiating the idea.