This list will be updated as I gather more of the Asterisk supported VoIP services. You can message me on Linkedin or Facebook with your suggestions. Be sure to point to this blog article.
Didx.net with over 12,500 wholesale members to buy and sell among 60 countries with a free UK and USA DID for testing.
MyDivert with USA and international call forwarding, each DID with zero setup fee.
Virtualphoneline.com with connection to Facebook and opp for a free USA phone number.
VoIPSWITCH for ip-pbx, switch, voip solution and even a Vippie mobile app!
... browse some of our team's other blogs at http://blogs.didx.net and http://blog.tmcnet.com/monetizing-ip-communications/. You're welcome to comment, contribute, and collaborate any time.