VoIP <--> PSTN provider recommendations

[VirginSnow at vfemail.net]

> Date: Thu, 6 Dec 2007 18:57:25 -0500

> I'm shopping for a new VoIP <--> PSTN service provider (so I can place
> and receive telephone calls over the Internet).
> 
> Does anyone have experience with good providers?  Any providers
> (besides NuFone) I should steer clear of?

I should also note that I'd prefer the service use standard protocols
(IAX, SIP, or similar) and that the service needs to have an open
source client.