changing file information for music

I have some mp3's on my computer, and I've noticed that if I right click them and select "Get Info", in the "More Info" section there is information like album name, genre, authors, title, and so forth. My question is, how do I change this information? I know that you can drag a file into the iTunes library and change it from there by right-clicking and editing it, but is there a way to change this information outside of iTunes, so that when I select "Get Info" for a file that has not been imported into iTunes, it says the album name and song title and so forth that I want it to say, and not the one it's set to now? Can I change that information?