I would suggest in person. That way you can discuss with them what you are looking for them to write as well as give them a copy of your resume. Also if its been awhile they might not recognize the name off the bat but might recognize the face. I would never ask for a LOR over email or phone unless they were not in my area. Then I'd ask over the phone. Much more personal.
While you really should do this in person, I had one Prof. that was REALLY busy (I think he was up for tenure.) When I tried to make an appointment to see him (he wasn't teaching classes that semester and didn't have any office hours,) he pretty much wouldn't agree to see me until I told him what it was about. I eventually asked him in email, and he said something like "Sure, I'd be happy to -- there's no need for you to stop by, just send me PDFs of your CV, etc."
I would highly recommend asking in person, however (which I did for all of my other LORs -- except for a former boss that now lives in India.)
i did it via email but offered to meet with them in person. i ended up meeting with one and just mailing the resume/personal statment to the others. i feel it worked out well but we'll see if I get in anywhere... I'm a bit social-phobic and so are most profs.
Hi mary, I can't vote because I'm doing it both face to face and through e-mail. One professor I need a letter from in is Virginia and I'm in Illinois. So e-mail is the best option for me. I also asked my current A&P II instructor for one last Thursday after class (our class ends in 2 weeks).
I called the college and found out that the professor was out for the summer so I send her an email. That worked. I mailed her a package with my info (PS, CV and transcripts) and then she mailed a letter to Interfolio. The second professor I went to see in the office. The third one I emailed and planning to see him soon. I think the best way to do it is to make an appointment and see them in person.