For the minority that use Macs that might like to know...
I used a .doc file for my resume on the application, then when I was emailed a request for my resume to me emailed back, I used a .rtf as well as a .doc version in case the format got zany in the translation. When I got the phone call there was no comment about it, but there were the std questions about the qualifications. I may ask at the interview if they had any problems with the one I sent. YMMV.