What do you mean, I can't just ask my roommate? For some publications, editors really like their writers to get a global perspective on a story, but interviewing long distance can be daunting. Here are some basic tips I picked up from writers I know who otherwise focus on domestic writing but have had to get international:

When dealing with an interviewee who has (or might have) a thick accent, it can be helpful to email questions before the interview, so that when you pose the questions in order, it can be easier to figure out the answers in context of the question asked. Otherwise, if you need a translator, this might be a good place to start if you need a freelance translator or agency. If you happen to be asking questions in real life via translation, don't forget to look at the interviewee, not the translator. And don't worry about 'dumbing down' your questions if you are using a translator; it's the translator's job to translate the questions.

If there is no translator on hand, be sure your interviewee has plenty of time for you to stumble through your language dictionary.

Don't be embarrassed: if you're not used to calling internationally, it's confusing. Here is a guide to the codes.

It's only 9:20 AM in California as I type this, but it's 1:20 AM in Manila. Don't wake somebody up. Know your time zones.

If a monetary issue is being discussed, be clear which currency is being utilized. If you have to convert, here's a site that does it for you. Did you know that I have the equivalent of 16.7 Swiss Francs in my wallet right now?