This may go against the norm, but I asked all three of my recommenders for LORs via email. They all know me fairly well, one is the director of my major who has also taught two of my classes. The other two are professors who have taught at least two of my courses as well. I have not seen the two professors for a few months and offered to send them a package with the LOR form, my resume and copies of work that I completed in their class. One of them didn't even need the information and forwarded the recommendation to me to read and fax with the cover letter on my own. The other professor did request the info but still said that he would be glad to write one for me. I see the director of my major often, but I initially asked her via email. I did stop by her office afterwards since I normally see her whenever I go to class. I believe it will depend on how close you are to the people that you are asking. The package that I did send out was very professional, and so were the emails, even though one of my professors is very cool and doesn't require a lot of formality. Only you know what kind of relationship you have with the people that you are going to ask and you should go from there. I have gotten two really strong letters from email requests and I'm sure the third one will be just as good.