Long distance = Yak or Yakcell
There are a few others, but this service is reliable, and the rates are competitive.
Phone cards = Mango or White Card
With phone cards, your minutes will be debited based on the country you are calling, and sometimes depending on whether the call is to a cell phone or a land line. Some cards expire after a fixed length of time. Get the $5 card unless you are using it frequently. The longer your individual calls are, the cheaper the minute rate is. If you make a lot of short individual calls, you'll find the total minutes run out fast. The end result is your total minutes can range from a half-hour all the way up to two hours, depending how you use it. All cards use this formula, more or less.