Does he have access to Skype, and would he be willing to use it? Recording a voice interview is often a lot better option than text. It allows for more genuine answers, and the file is also easier to repurpose in a number of different ways. I think Skype charges a small amount for recording conversations, I'm not certain, but if you have a digital recorder then it could be done with that too. Using their recording services will get you the best sound quality, though.
As for the time zone -- no matter which time zone, it's always best to find out what time is best for the interviewee, then adjust your own schedule accordingly.