I don't think it's a good approach to attach your resume or PS in your first email to any professor. Most professors would not like to read these emails as/if you didn't seek their permission. The most important thing to contact professors is to prompt their interests in you first with a short, concise email. After you get their interests, you can ask for their permission to send your resume and PS.
The professor who replied to your email is indeed nice.
Thanks for the advice. This would be the first and the only contact I would send to a professor at B-school. Afterall, I don't have any significant research experience to talk about. All I can do is to express my interest and determination.
Anyhow, good luck with everyone who applies to PhD in Business this year, eps. those who are still in their senior year at college. I am expecting a higher rejection rate for undergrad than the grad students.