E-mailing Professors?

[bronxblues24]

Hi everyone.

I was wondering if anyone had any experience emailing prospective professors? I have hit a snag in my research for comp lit programs and would like to ask professors some questions for clarification. However, I am unsure if this is wise. Should I just call/write to the program director instead? And in general, what is the etiquette in doing things like this?

Thanks in advance.