Check out Vonage.com.

Voice over IP on your existing broadband connection.  You choose the area
code you want, so you can have a NYC number here in minneapolis.  $19.95 a
month with 500 mins long distance, and only $39.95 a month for *unlimited*
long distance.  A guy I work with got it a couple of weeks ago and said it
rocks.  Plus, one of the area codes available is a NYC cellular area code.
NY has strict laws that prohibit telemarking to cell phones, so most
telemarketing firms remove numbers with this area code from their lists.  

They send out a Cisco ATA-186 box for you that you just plug into your
network, and plug into your phone network (after disconnecting the telco
drop first).  Open port 5060/UDP on your firewall so you can receive
incoming calls, and you're all set.  I used one of these boxes last year
when I was beta testing the FreeWorldDialup project (which seems to have
disappeared, but I still have the box :).  These things work sweet.  I
talked to another beta tester who was on a satellite link in austrailia with
300-500ms latencies, and you couldn't even tell.  Sounded like we were on a
normal landline.  No skips or drops in sound either.  That amount of latency
may seem like a lot, but if you have two cellphones and call one from the
other and put them up to both ears and talk into one, you'll see that the
latency is almost a full second. (nice run on sentence huh?)

I think I might dump my line at home for this thing.  I'm sick of figuring
out long distance charges for my 3 roomies, and our phone bill is like $80 a
month now anyway.  

Jay