http://voip.ms http://voip.ms is pretty decent and offers a few nice features that can avoid building an on-site PBX. I use this with good Polycom "HD voice" d

http://voip.ms http://voip.ms is pretty decent and offers a few nice features that can avoid building an on-site PBX. I use this with good Polycom "HD voice" devices. I'm also rather picky about voice quality.