I use this company. The system includes eFax, toll free and local number, live call transfers to any phone (your cell, desk etc), voicemails, conferencing, and low International calling rates. It is all virtual and doesn't disrupt any existing services.

They are also my client and I was formerly employed by them, just so you know I have a bias

http://www.cellplusplus.com

Also, there is apparently some industry research indicating many people do not like to call long distance numbers, even if it is free for them. I will search to see if I can find a link.