Phone.com launched back in December. For a $29.95 start-up fee and $16.88/month (annual plan) you get unlimited inbound and outbound domestic calls, your own DID, an ATA and all the standard features you’ve come to expect (voicemail, caller ID, call waiting, etc — see their features page). You can pay monthly and you can opt for a plan that only offers 200 minutes — see their pricing and plans page.