You can port the number to your DID provider. Most people use bandwidth.com but flowroute and voip.ms are also ones that are thrown around a lot. Most of them c

You can port the number to your DID provider. Most people use bandwidth.com but flowroute and voip.ms are also ones that are thrown around a lot. Most of them charge <$5 for porting. OS Integration is possible only through 3rd applications (unless you have android which has a native SIP stack on the device) like Groundwire or Bria. It uses megabytes and I believe, if you're using G.711 (the normal cell codec) you'll consume data at 64kbps (peak). I've never gone over on using it but YMMV. iOS integration is tricky because of the "keep-alive" strategies designers have to use. The VoIP app has to be able to notify on inbound calls, but that is usually only possible when the app is in the foreground. There are some cool hacks to get around this (I like the groundwire message personall). Text messaging is dirt cheap; many providers will give you unlimited usage for very cheap (I've seen it as low as $.40 per DID per month). You could use twilio, but you'd be better off with tropo since it's more open (sort of, not really the time or place for that sort of debate). Edit 2: Yes you can. I think I answered everything :). You can do all of this for free (except for usage) if you install the 2600hz kazoo stack (here's the Chef-Solo install instruction set: https://2600hz.atlassian.net/wiki/display/docs/Deploying+Kazoo+with+Chef+Solo https://2600hz.atlassian.net/wiki/display/docs/Deploying+Kaz...). You can also do a hell of a lot more than just call forwarding :). We're fully open-source, it's free, and it has all of the APIs you're looking for when building kickass mashups. A hosted version should be more widely available in Q1 next year.