Cut to the chase - the easiest thing for occasional "I'm OK" calls is a prepaid AT&T long distance card from some place like Sam's Club. I think BJs sells an equivalent card from MCI. With a little research beforehand you'll know the number to call within any particular country to reach the automated AT&T operator (just like when you call 1-800-CALL-ATT from the US). Here's a link to downloadable wallet cards with USA-Direct numbers.

There are cheaper methods per-minute but this is easy. I think you end up spending $15 or $20 for the smallest card Sams sells.