Hi, I'm planning on traveling to the US and Europe in the near future
> so I'd appreciate some recommendations on which providers I should use
> for cell service and phone/calling cards.
You apparently will be coming from Australia. How long are you planning to be in the U.S. and in Europe? In which European countries will you be traveling, and for how long? There are different answers to your questions depending on how long you will be in various places.
Michael D. Sullivan Bethesda, MD (USA) (Replace "example.invalid" with "com" in my address.)