I've heard that Onsip is a great option for setting up a large amount of phone numbers. Obviously this is mainly for businesses that need to set up hundreds and hundreds of listings all over the USA. If you only need to set up a few numbers, it is probably cheaper in the long run to use Vumber or Skype or something. But $7 per phone number and $2/month ongoing is a great price. Question is, do any of you use it? What has been your experience?