I have a Blackberry and have used GoogleVoice to make calls over my data connection (which in the lounge could have been via the wi-fi if I had taken the time to set up connection). GoogleVoice is sometimes iffy and I needed an answer quickly so I bit the bullet and make a long distance call. I have an international voice/data plan so the cost/min is lower than roaming but its still pricey enough that I always try GoogleVoice or Skype on the laptop.

Fortunately the call was not long.