Cheryl is still here (for one more day) and because he may use some of this material in one of his podcasts, we figured he'd want better audio than he would get with the two of us talking to him on the speakerphone, so we needed to both be on headsets. That meant we needed to use Skype, so we could each call from our respective computers. Also, the rate to call Mexico city was only about 2.4 cents/minute, a lot less than what it would cost on the landline phone.
At first not quite realizing what we'd have to do, I figured that both Cheryl and I would need to have some Skype calling credit, and we'd both call Mexico City. Later (unfortunately after I'd bought €10 worth of credit) -- I realized that it made more sense to do a Skype conference call, with me first conferencing Cheryl's Skype account (free), and then calling Roberto. That way we only had one call that was costing money, and indeed the 40-minute call cost less than €1.
This setup worked well, except for the noticeable delay on the audio -- enough that Cheryl took her computer into the living room so that we could only hear each other over the Skype line, not "live" in the same room.
Aside from confusing the person who answered the call and getting initially routed to the wrong person (my fault), the interview went pretty well, I think. I'm looking forward to seeing/hearing what, if anything, he can do with the material. Cheryl and I are happy to help publicize Worldcon, the Hugo Awards, and SF/F in general.
I want to apologize to