I use Gorilla Mobile http://gorillamobile.com

I dial a NYC number 212-430-0425 and from there I can call any
internationally dialable number.  Calls to western Europe generally
are 5¢/minute to wireline phones.  More expensive to call European and
Asian mobile numbers.  It is "PIN" less once you register with
gorillamobile.  Also have access through a toll-free 866 number but
there is a 15¢ per call surcharge.  $5.95 fee per year of use.  I've
used them for over three years and the quality of transmission is
good.

"Dialaround" so called "10-10" providers don't work on any mobile
phone services probably because mobile services aren't required to
offer alternative long distance carrier availability.
- - - - - - - - - - - - - - - - - - - - - - - - - -