I just signed on with EverDial, www.everdial.com.
No monthly fee whatsoever, and 4.9 cents state to state 24hrs a day. I also locked in 8 cents a minute to the UK/Ireland 24hrs a day. Billed in 6 second increments, not rounded to the next minute. It took a couple of months of research to find these guys with these rates.
Worth a look.