http://voipbuster.com provides free outgoing calls to the PSTN to over 60 different countries. The service is free. More information can be obtained from there website. You do initially have to download and install the softphone to set up your account, even if you plan on using the service with an ATA or SIP phone.
They do not however provide free DIDs, but that is where http://ipkall.com comes to the rescue. Ipkall will give you a free Washington state telephone number for any SIP service provider that you currently use. So paired with voipbusters service you could have a completely free home telephone service for incoming and outgoing calls.
So you say that you want a local phone number? That is OK. You just head over to http://google.com/voice and sign up for a google voice number. have your GV number forward to your ipkall number, and when someone calls your GV number, your voipbuster phone will ring.
you can also obtain free incoming calls with GV and http://gizmo5.com but gizmo is currently in closed beta, and not accepting new sign ups. Besides, the GV + Gizmo set up does not provide you with free outgoing calls, unless you use the click to call interface from the website, and who wants to dial numbers like that?
I know I just posted this blog, but I have additional information to add to it already...
http://voipstunt.com/en/index.html supposedly gives you free SIP phone service, as well as calls thru an access number. I have not had the opportunity to test this service out myself yet, but felt the need to provide the information here. (The website seems like it has a similar set up as voipbuster, so perhaps it is the same company)